Thermoelastic stress analysis (TSA) is a non-contact and full-field type method of experimental stress analysis. Since TSA provides only the sum of the principal stresses, many studies have been carried out for developing techniques of stress separation. Unfortunately, most of the techniques developed hitherto are rather complicated and require much labor in practical application. Recently, the authors have developed a simple technique by utilizing the nonlinearity of the thermoelastic effect. In this technique, principal stresses are determined from two sets of temperature amplitude data measured under sinusoidal loadings of same amplitude and different mean values. However, the difference between temperature amplitudes obtained at different mean loadings is very small and, therefore, the result of stress separation becomes very noisy. In this paper, several smoothing techniques are applied to the temperature amplitude data. It is found that some simple smoothing techniques are effective for improving the accuracy of the stress separation.

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Many traditional methods of full-field strain analysis provide convoluted or limited strain data. For instance, photoelasticity provides data related to the difference in principal strains and strain separation is problematic; whilst moire can provide in-plane or out-of-plane displacements. It has long been recognized that integrating two techniques can enhance the information available, for example holophotoelasticity; this is particularly valid when one technique operates in the infrared spectrum. Combined thermo-photo-elasticity was first attempted about a decade ago and an instrument for simultaneous capture of thermoelastic and photoelastic data has been developed and used to acquire maps of separated principal strains in complex components. When thermography and moire are combined, a new technique emerges which allows measurement of in-plane and out-of-plane strain. These novel techniques are described and examples given of their application to strain measurement in composites and complex engineering components.

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This paper describes an experimental study on full-field stress separation from thermoelasticity and photoelasticity measurements and its application to estimation of stress intensity factor and the J-integral. Thermoelastic stress analysis (TSA) and photoelastic stress analysis (PSA) have been developed as full-field visualization methods of stress distribution. Only the sum of principal stresses can be measured by TSA, while only the difference of principal stresses can be measured by PSA. In this study, the hybrid stress separation measurement technique developed by the present authors using both of these methods was applied for determining distribution of all individual stress components in a center-cracked plate subjected to mechanical load. Stress intensity factor and the J-integral were calculated from the obtained stress distribution. In addition to the conventional calculation method, near-tip exclusive domain integral method was proposed, in which the J-integral was evaluated without using degraded experimental stress distribution data near the crack tip. It was found that these fracture mechanics parameters can be evaluated with good accuracies by the present technique.

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The development of new techniques for the measurement of contact pressure distributions between bodies in contact is of large interest in mechanics, for the design and verify of many couplings between mechanical components. Examples are the contact between tooth of gears, between the balls and rings of ball bearings, between the wheel and rail etc. In this paper a new measurement technique is proposed, based on the measurement principle known as thermoelasticity. The particular case about the measurement of contact pressure distribution between a ball and a flat plate is discussed. Previous studies was performed in order to examine the contact surface between the two bodies realizing one of the two bodies in contact using an infrared transparent material, with appropriate values of the other mechanical properties. These studies were anyway only qualitative. In the present work, two calibration methodologies are proposed to obtain measures of contact surface stress between a ball and a flat. One of these methodologies is based on experimental test and the other one is based also on analytic results. The measured stress behaviours are in agreement with the classic Hertz theory; relative uncertainty is smaller then 0.1. This allows to obtain first quantitative results of contact pressure distribution by using thermoelasticity.

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In this work the mechanical behaviour of the blade, has been studied using thermoelastic analysis. This measurement technique permit to correlate the thermal variation, induced by a cyclic load, with the stresses distribution on the knife blade. The image of superficial stresses acquired by thermoelastic system (Deltatherm 1550) has been compared with FEM analysis results directly.

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The stress concentration factors and stress intensity factors evaluated by thermoelastic stress analysis method were lower than the comparable values calculated by the finite element method (FEM), and the error increased in proportion to those values regardless of the stress ratio. In this study, the sources of the error between experimental results and numerical values were investigated in order to improve the accuracy of thermoelastic stress analyses. Since the major source was supposed to be the effect of heat conduction in specimens, the unsteady heat conduction analyses were conducted for three types of center holed specimens and center crack tension (CCT) specimens. According to the comparison between experimental results and numerical values, it was found that stress concentration factors were affected by heat conduction especially under 10Hz, but the errors of stress intensity factor were caused not by heat conduction but by the plastic zone size of a crack tip.

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Experimental techniques for measuring temperature fields at the tool-chip interface during machining and in the workpiece subsurface during grinding are described. Both techniques involve measurement of the radiation emitted by the region of interest using a Charge-Coupled Device (CCD) based Infra-Red imaging system, yielding non-intrusive full-field in-situ measurement of temperature at high spatial and temporal resolution. In the case of machining, a key element in the measurement technique is the use of an optically transparent sapphire tool, which has enabled direct images of the tool-chip contact area in the infra-red. Principal characteristics of the temperature field such as the variation of temperature with position along the interface and the location of the region of highest temperature are identified. The implications of this measurement to the understanding of the tool-chip interface at the micro-scale are briefly discussed. In the case of surface grinding, the technique involves measurement of the radiation emitted by a side of the workpiece immediately adjoining the wheel-workpiece contact region, providing an accurate estimate of the in-situ surface and sub-surface temperatures in the workpiece. It is shown that by appropriate analysis of the temperature data, the heat flux profile in the grinding zone and the contact length between the wheel and workpiece can be estimated. Results indicate that the shape of the heat flux is triangular and that the actual contact length is greater than the geometric contact length.

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Paper emphasizes thermoelastic applications to determining individual stresses, orthotropy, composites, fracture mechanics, connections, material response, graded materials and three-dimensions.

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Tantalum thin films have been preferred in case of corrosion protection in the chemical industry of high temperature applications because of its long lifetime and low service costs. Residual stress could be generated during thin film elaboration and they influence the film use properties. So, the residual stress level should be correctly determined especially in the case of stress gradient. X-ray diffraction (XRD) stress analysis is a local, non-destructive, quantitative method to study thin films. In the case of stress gradient, pseudo-grazing incidence X-ray diffraction (GIXRD) should be used in order to evaluate the residual stress distribution. Based on bibliographic works, a modified method has been developed for GIXRD stress analysis with the calculation of geometric adapted real angles ?'. This method allows more practically the determination of near surface stress gradient in specific direction and we name it sin^2? ' method. The developed new technique was applied on three Tantalum thin film specimens with different thickness (from 0.55 to 2.55μm) obtained with CVD process. The technological limits have been studied with different crystalline families, different incident radiations (Cu and Cr) and different GIXRD conditions (variable incidences). Then, GIXRD has been carried out both in a and β phases and residual stress distribution has been obtained for each of phase with selected family plan. The obtained residual stress level and their distribution were quite comparable with those determined by other GIXRD methods.

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Welded joints are used for construction of many structures. Residual stress is generated near the bead because of locally given heat. Tensile residual stress on the surface degrades fatigue strength. In this paper, a new method for reduction of residual stress using random vibration during welding is proposed. As random vibrational load, filtered white noise is used. Two thin plates are butt-welded. It is found that tensile residual stress near the bead is reduced by using random vibration. Reduction of tensile residual stress is examined by simulation method using simplified analytical model. It is concluded that reduction of residual stress can be demonstrated by using the proposed model.

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Several hard X-ray imaging techniques greatly benefit from the coherence of the beams delivered by modern synchrotron radiation sources. This is illustrated with examples with ferroelectric materials on BL47XU, an undulator beamline at SPring-8. There is two types of ferroelectric domains in barium titanate (BaTiO_3) at room temperature tetragonal phase; one is 90°- and another is 180°-domain configurations. Around the ferroelectric domain boundary, a large strain exists to compensate for different lattice parameters. In 90°-domain configuration, the strain is equal to a simple type planar defect, that affects the ferroelectric properties seriously. The topographic image of the ferroelectric domain boundary will give much information about strain transmission process, and micro-domain induced structure like domain-engineering ferroelectric materials. By combining the optical microscope and X-ray topography, the lattice-strained region at domain boundary was observed and the mechanism of lattice-strain relaxation was understood. In the pure BaTiO_3 single-crystal with large ferroelectric domains, the size of lattice-strained area was of μm order.

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A large penetration depth of high energy X-rays makes it possible to measure nondestructively the residual stress in the interior of the top coating in the thermal barrier coating (TBC). A new hybrid method is proposed to estimate the distribution of the spalling stress in the top coating by combining the synchrotron data with the stress data measured by the conventional X-ray method utilizing a Cr-K_α radiation. The new hybrid method was applied to estimate the distribution of the spalling stress in the top coating of TBC which had a zirconia top coating with a thickness of 0.24 mm and a NiCoCrAlY bond coating with a thickness of 0.2 mm. The residual stress, σ_<11>-σ_<33>, within the top coating was determined by synchrotron X-rays of 73keV energy level, where σ_<33> was the stress perpendicular to the surface and σ_<11> was an inplane stress. The distribution of residual in-plane stresses, σ_<11> and σ_<22>, in the top and the bond coating was determined with the conventional X-ray method by repeating the measurement after successive removal of the surface layer. From the data obtained by synchrotron and conventional X-rays, the distribution of stress component, σ_<33>, responsible for spalling was determined. The estimated value of the spalling stress was very small beneath the surface and increased to about 75 MPa near the interface between the top and the bond coating.

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This paper covers the recent progress in two-dimensional X-ray diffraction theory and applications in structure and stress analysis. Two-dimensional X-ray diffraction refers to X-ray diffraction applications with two-dimensional detectors and corresponding data reduction and analysis. The two-dimensional X-ray diffraction provides far more information than the conventional one-dimensional diffraction. The structure information, such as grain size and preferred orientation, can be observed directly on the two-dimensional diffraction image. Phase identification can be done by integration over a selected range of diffraction rings. The integrated data gives better intensity and statistics, especially for those samples with texture, large grain size, or small quantity. The two-dimensional detector collects texture data and background values simultaneously for multiple poles and multiple directions. Stress measurement using two-dimensional detector is based on a direct relationship between the stress tensor and the diffraction cone distortion. Since the whole or a part of the Debye ring is used for stress calculation, two-dimensional system can measure stress with high sensitivity, high speed and high accuracy.

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Sintered Fe-Cr alloy containing TiN particles has high wear and heat resistance. These materials have been developed for the valve seat insert, which is a part of automobile diesel engines. In this study, X-ray and neutron diffraction techniques were used to carry out residual stress measurements of composite material, in order to evaluate the stresses in each phase. The influence of inclusions (titanium nitride) on the residual stress was examined. Measured data obtained from both phases were compared to the micromechanics model based on Eshelby's approach and the Mori-Tanaka theorem. The range of applicability of the theoretical expectation in the determination of the residual stress in composite material was investigated. It was found that (1) in the case of the neutron diffraction technique, the matrix 110, 200 and 211 diffractions were observed in the matrix (Fe-Cr)phase. The 111, 200, 220, 311 and 222 diffraction peaks were observed in the TiN phase. (2) The change in the stress of each phase under an elastic load was examined. Individual phase stresses in the matrix and TiN increase proportionally with the applied stress, and the ratio of the amount of change to applied stress indicates that the TiN phase is more abundant the matrix.

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A hypereutectoid steel with chemical compositions of 0.85C, 0.24Si, 0.82Mn, 0.011P, 0.01S, 0.02Al and 0.05Cr in mass% was hot-rolled and patented through an industrial process to produce fully pearlitic structure (P1). Specimen P1 was then drawn by 75% in area reduction (P2) and aged at 698 K for 0.6 ks (P4: Zn-plating simulated heat). Textures were measured on these specimens and evaluated by (110) pole figure. The orientation distribution of P1 shows approximately random while that of P4 is sharp <110> fiber texture along the drawing direction. Tensile tests were performed for P1 and P4 and neutron diffraction measurement was conducted for their deformed specimens. By using a conventional θ-2θ method, lattice plane spacing of (110) ferrite was measured, where a specimen was rotated by 0, 22.5, 45, 67.5 and 90 degrees with respect to the tensile direction. The residual elastic strains for P1 and P4 show the strong direction dependence; as an overall trend, the strain changes from compression to tension with increasing the measuring angle from 0 to 90°. However, in the case of P4, the residual strain at 90°is lower than that at 67.5°. It is concluded that the <110> fiber texture is attributed to the low residual strain at 90°.

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It is reported that deposited TiN thin films have preferred orientation in recently years. Those films have the fiber texture structure. However, TiN thin films having [111] fiber texture near the single crystal structure by physical vapor deposition was treated in this study. There is no procedure to evaluate the stress-strain state for such sample. Therefore, a new procedure of X-ray stress measurement for single crystal having [111] fiber texture is proposed. In addition, the procedure is compared with precedent procedure up to present. The crystallite orientation was evaluated by the pole figure, and the residual stress was measured using Cu-Kα radiation with three methods. METHOD1 is the model of polycrystals, METHOD2 is the model of single crystal and METHOD3 is the way used a convenient measurement technique that is proposed by Tanaka et al. for single crystal. As a result, the stress using the single crystal model and using the polycrystals model had similar value. In METHOD3, the value between σ_<11> and σ_<22> made a little difference.

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The influence of residual stresses as well as of loading stresses on microhardness is systematically investigated using a combined application of registered microhardness measurements and stress analysis by X-ray diffraction in order to evaluate the ability of the microhardness testing to estimate residual or loading stresses, respectively. Measurements were carried out on steel samples of type S690QL and SAE1045 using a conventional Vickers indentor as well as a ball indentor. The investigations cover samples subjected to 4-point bending as well as uniaxially loaded samples. The investigations show that loading as well as residual stresses have a marked influence on the results of registered microhardness measurements. This effect overlaps with consequences of strain hardening and influences hardness distributions in case of the 4-point-bending experiments as well as in case of the uniaxially tensile loaded samples in a characteristic way. It becomes visible that the microstructure of the tested steel samples as well as the type of the indentor have a significant influence on the correlation between the applied load and the resulting change in hardness. As a conclusion, it appears to be ambiguous to deduce residual or loading stresses directly only from results of microhardness readings, in particular as it cannot be accounted for the effect of directionality of microstructure and applied loading state on the results of microhardness testing.

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The purpose of this investigation is to clarify the influence of an internal fatigue crack on surface actual stresses in the circumferential distribution. The cantilever rotary bending fatigue tests were conducted on the shot-peened nodular graphite cast iron specimens. The actual stress distributions in the surface at the maximum tensile applied stress were dynamically measured by the X-ray stress measurement based on single exposure technique during fatigue testing. The circumferential distribution changed with increase in the number of cycles. Residual stress distributions were also measured under unloading. The possibility to detect the internal crack using change in these distributions was discussed. As a result, from observation of fracture surfaces, it was confirmed that the peak position in the actual stress distribution agreed with the internal crack position. The internal crack causes the peak in the distribution. The method proposed in this study is useful for detecting a position of an internal crack on specimen circumference. On the other hand, the residual stress distributions showed no significant change even where the internal crack existed, whereby the internal crack could not be detected by change in the residual stress distribution.

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The X-ray diffraction measurements based on the grazing incident geometry were applied to determine lattice strains in polycrystalline materials. This method enables a non-destructive measurement at chosen depth below the sample surface. The volume, for which the stress is measured, is well defined and it does not vary during experiment. The multireflection method was used for analysis of the experimental results since the interplanar spacings were measured for various orientation of the scattering vector as well as for various crystallographic planes {hkl}. Applying two different wavelengths of X- ray radiation and various incident angles a non-destructive measurements of the residual stresses in function of penetration depth were performed. The variation of stresses in plastically deformed surface layers of steel samples was successfully determined and the values of the stresses were confirmed by standard diffraction measurement.

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A neutron image plate (NIP) was developed recently as an area detector for the neutron experiment. It will be possible to obtain strains along the line in the material where neutron beams penetrate from a Debye-Scherrer ring on the NIP. Since the diffraction ring contains continuous and different oriented strains, the depth profile can be determined more correctly as well as quickly than the ordinary method. In this study, we attempted to find out the possibility of the NIP for the stress measurement. As the first step, an observation of neutron diffraction rings was performed on the 211 diffraction of a steel. The influence of the thickness of the material as well as an incident angle on the diffraction ring was investigated. A simple tensile test was also performed and a diffraction image was analyzed to investigate the relation between the deformation of the diffraction ring and the tensile stress.

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The aim of the present paper is to clarify the residual stress occurring in the c/c composite to improve the manufacturing process. The residual stress was measured by a neutron diffraction method using the RESA in the JRR-3M of JAERI in this study. As a results of the residual stress measurement, it was found that the residual stress of the ring type c/c composite is the compressive stress, and that the macroscopic residual strain/stress is absorbed mainly microstructural change such as pore shape change.

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The stress measurement methods by using Neutron and X-ray diffraction were examined with regard to compare the surface stresses with the internal stresses in the continuous tungsten-fiber reinforced copper-matrix composite. The surface stresses were easily measured by X-ray stress measurement with ordinary sin^2ψ method. However, for the internal stress by Neutron diffraction, the most common triaxial measurement method with Hooke's equation was only possible to measure about 110 plane, because the tungsten fiber became the situation of heavy 110 orientation. Therefore, the stress values against 200 and 211 plane could be determined by employing the sin^2ψ method used with Neutron diffraction. The d- sin^2ψ diagram was shown the good linearity in not only 200 plane but also 110 and 211 plane. Clearly, the stresses are possible to be determined by the gradient of sin^2ψ diagram in the Neutron stress measurement. However, if the sin^2ψ method was applied in the Neutron stress measurement, the stress σ_<11>-σ_<33> was estimated in the inner part of the body due to the existence of the σ_<33>. These influences of the stress σ_<33> were discussed in this study. Furthermore, the microstress distributions were calculated by the three-dimensional FEM elastic analysis and compared with the experimental results.

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The thermal residual stress at the internal positions of central circular sectional plane of an induction hardened S45C round bar was measured nondestructively by neutron diffraction. The neutron diffraction equipments, RESA installed at JRR-3M reactor and Sirius at KENS were used. We observed the SEM image of the sliced specimen cut from the round bar to investigate the existence of martensitic phase. The sliced specimen was also used for the determination of the stress free lattice spacing in the case of coexistence of martensitic phase and ferritic phase. The Young's modulus and the Poisson ratio were obtained by the neutron diffraction of the specimen for tension test. As a result, the residual stress for radial direction at the surface of the bar is nearly equal to zero, and those for hoop and axial directions are near -900 MPa, which is largely compressive. These three stresses gradually increase to tensile one as we approach the center of the sectional plane. These results show a good coincidence with the result of FEM analysis.

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The residual stress distributions near the laser-irradiated line in a crystal grain of the grain-oriented silicon steel sheet were studied by the X-ray stress measurement method for a single crystal, in order to clarify the mechanism of the magnetic domain refinement. The distributions of residual stresses were measured before and after the stress-relief annealing. The change in magnetic domain structures was also observed in this process. After the laser irradiation, the refinement of magnetic domain was observed. In addition, the inhomogeneous deformations such as plastic strains were induced near the laser-irradiated line, and the tensile residual stresses of 50-200 MPa were generated. Moreover, the slight compressive residual stresses were recognized in approximately 0.15 mm depth from the laser-irradiated surface. However, these compressive stresses did not affect the magnetic domain refinement. After stress-relief annealing, the residual stresses were relieved, and the magnetic domain then returned to its original width. Therefore, it was supposed that the change in magnetic anisotropy induced by the local plastic strain generates the 90-degree magnetic domains near the laser irradiation and that the local tensile stresses near the laser-irradiated line destabilize theses 90-degree magnetic domains so as to refine the 180-degree domains.

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Residual stresses in TiN and TiAlN films on steel substrate were investigated by the usual in-lab X-ray equipment and ultra high X-rays of synchrotron radiation. The specimens prepared in this study were single TiN films with different thickness on the stainless steel substrate and single-, double- and multi-layer TiN and TiAlN films deposited on high speed steel substrate by arc-ion plating. The minimum thickness available for the residual stress measurement was 0.8μm by in-lab equipment whereas below 0.1μm by synchrotron radiation. Extremely large compressive residual stresses were found in the films and the level of residual stress was almost constant regardless of the film thickness. Residual stresses in TiAlN films were more than twice larger than those in TiN films, resulting to reduce the average residual stress in the whole film system by making double- or multi-layer film construction comparing to that in the single TiAlN film.

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Gallium nitride powder is employed as a target material for sputtering deposition. A powder target offers the merit of easy formation of an n-type or p-type semiconductor film. In this study, the effect of the powder target is investigated. Crystal orientation and residual stress in GaN films deposited by radio frequency (RF) sputtering with the powder target are investigated by X-ray diffraction (XRD) as functions of nitrogen concentration (C N2 ) in the atmosphere gas consisting of argon and nitrogen. In addition, the film surfaces are observed by atomic force microscopy (AFM). The following results are obtained: (1) GaN films deposited by sputtering with the powder target attained good crystal orientation, with the c-axis oriented normal to the substrate surface; (2) film thickness decreased with increasing nitrogen concentration (C_<N2>); (3) the film deposited at C_<N2>=20% had the largest crystal grain size, and the film deposited at C_<N2>=0% had the smallest; (4) the film deposited at C_<N2>=20% had the smallest degree of c-axis orientation, and that deposited at C_<N2>=0% had the largest; (5) tensile residual stress occurred in films deposited at C_<N2>≦20%, and compressive residual stress over -1 GPa occurred in films deposited at C_<N2>≧50%.

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The residual stresses and crystallographic structures of Cu/TiN multi-layer films deposited on glass substrates are investigated. The TiN layers are first deposited by arc ion plating onto the substrate, followed by Cu films deposited by plasma coating or RF sputtering. The rystallographic structure and residual stresses in the multi-layer films deposited as a function of the thickness of the TiN layer are then investigated by X-ray diffraction. The TiN layers deposited by arc ion plating on glass substrate are found to exhibit strong {111} orientation. The Cu layers deposited by both plasma coating and RF sputtering on top of the TiN layers are also found to exhibit strong {111} orientation. The two-exposure method is used to evaluate residual stresses in the Cu and TiN layers by measuring lattice strains in two directions determined from the crystal orientation. In the case of RF sputtering, the Cu and TiN layers in the Cu/TiN film are found to exhibit tensile residual stresses of 450〜630 MPa and 230 MPa, respectively. In case of plasma coating, however, the Cu and TiN layers in the Cu/TiN films exhibit tensile residual stresses of 180〜240 MPa and 300 MPa, respectively

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This paper describes a fundamental study on the possibility of a new type of the X-ray stress measurement, in which stresses are obtained from analyzing whole part of one diffraction ring detected with a two-dimensional X-ray detector called image plate (IP). The theory of the stress determination proposed by Taira and Tanaka (1978) was shown first, and then newly modified to be able to determine all plane stress components from a single-exposure experiment. An experiment was performed for the examination of the method, and the result of showed good agreement with stresses that were applied to the specimen mechanically.

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Neutron diffraction method has attracted much attention in recent years to measure residual stresses inside of the material by using high penetration power of neutron ray as one of non-destructive detection technique. It is necessary to know the non-distortion angle to measure stresses distribution inside of bulk material. However, during heat treatment such as quenching, since phase transformation near surface modifies the microstructure of the material, determination of the residual stresses is very difficult considering the gradient distribution of martensite. In this paper, residual stress in the quenching material with phase transformation is measured using the neutron diffraction method. Moreover, from metallo-thermo-mechanical theory, simulation using the coupled analysis by finite element method is carried out, and the residual stresses in materials are predicted. Then, experiment results and calculation value are compared and examined.

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This paper describes an application of a new type of X-ray stress measurement, which uses whole part of the diffraction ring for determining stress. The method can be also applied for the measurement of both macro and microstresses in composite materials. In case of measuring a dual phase stainless steel, the diffraction rings, which come from both austenitic and ferritic phases, can be recorded on the same area detector when chromium Kα radiation is used. In order to check the validity of the method, the stress obtained by this method was compared with the stress that was applied to the specimen mechanically. A volume fraction of each phase was also determined from the diffraction intensity of the diffraction ring. The present method was applied to analyze an area around a notch tip of a dual phase stainless steel.

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Two unconventional high-resolution monochromator performances using Bragg diffraction optics and based on cylindrically bent perfect crystals which have been recently tested with the aim of their efficient employment in strain diffractometers are reviewed. It has been found that the optimized diffractometer arrangements employing such monochromators provide good luminosity and a high resolution (FWHM of the instrumental Δd/d - profile can be about 2.7x10^<-3> in the double-crystal case or less than 8x10^<-4> in the Umweganregung case) in the vicinity of usually used 2θ_S &ap; 90°. Presented results demonstrate their experimental abilities for powder diffraction, namely for residual strain/stress measurements. Due to the unique resolution and good luminosity achieved, besides the macrostrain scanning, the presented performances also qualified for possible microstrain/stress studies by an analysis of the diffraction profiles.

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In evaluation of fine ceramic components reliability, it is very important to know residual stress introduced to the material surface in the fabrication process. X-ray diffraction method has been sometimes used to measure the residual stress for ceramics, but there are some difficulties in both high cost and exposure of harmful radiation. In order to overcome such difficulties, a simple indentation method to measure the residual stress was proposed by a committee in JSMS. In order to verify this method, the residual stress induced by a vice was actually measured. The residual stress thus obtained was in good agreement with the stress artificially provided by a vice.

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A method for evaluating stress distribution along crack under mixed-mode condition (Modes I and II) and stress intensity factor is proposed through measurement of crack opening and sliding displacement distribution along the crack. Based on the present method, residual stress distribution along the fatigue crack and stress intensity factor for Mode I are experimentally evaluated from the crack opening displacement distribution measured along the crack in a finite plate specimen. The evaluated stress distribution along the crack is in close agreement with the residual stress distribution measured by an X-ray. The stress intensity factors obtained by the present method are influenced both by the residual stress and by finite width of the specimen.

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The effects of the thickness of the sputtered Cu thin films and the substrate material on the residual stresses and mechanical properties of Cu thin films were investigated. The thickness of Cu thin films was varied in the range of 0.5 to 3 μm. The substrate material was a glass (Cu/glass specimen) or a single crystal Si (Cu/Si specimen). The specimens that PTFE was inserted as a middle layer were prepared for the Si substrate (Cu/PTFE/Si specimen). Residual stresses of Cu thin films were measured using a synchrotron radiation source. The hardness and elastic modulus of Cu thin films were measured using a nanoindentation method. The crystallite size of Cu thin films was evaluated by micro-beam X-ray analysis. The tendencies of the residual stress against the thickness of Cu thin films were greatly different depending on the substrate material. The crystallite size of Cu/PTFE/Si was smaller than that of Cu/glass. This fact corresponds to the result that the hardness of Cu/PTFE/Si is higher than that of Cu/glass. The elastic modulus and hardness decreased with increasing the indentation depth. Therefore, it is considered that the mechanical properties have a certain depth distribution in the direction of the thin films.

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We have demonstrated to form an x-ray microbeam with a narrow angular divergence in both vertical and horizontal polarization directions of synchrotron radiation x-rays by the use of successive asymmetric Bragg reflections. Using the highly parallel x-ray microbeam thus obtained, we are able to analyze the local minute strain of less than 10^<-5> in semiconductor materials and devices. A series of x-ray rocking curves have been obtained by scanning the sample against the x-ray microbeam. Variations of the reflection peak intensity, angular shift value and/or half widths inform us how strain is distributed in the materials with high spatial resolution. In addition, reciprocal space maps have been drawn with an analyzer crystal put behind the sample on the x-ray path. From those data, strain distribution can be analyzed in terms of both lattice tilt variation and lattice parameter variation independently. Strain near Si-oxide film edges on Si substrate or that in silicon-on-insulator (SOI) crystals or other semiconducting materials has been measured. The results of reciprocal space maps have shown that the strain in the bonded SOI layers is mainly due to the lattice tilt variation rather than the lattice parameter variation.

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A second harmonic YAG laser beam collimated was irradiated on the surface of both ferritic and austenitic steel specimens with various peening conditions. The residual stresses on the laser irradiated surface and the depth profiles of residual stress near the surface of specimens were measured using a characteristic x-ray and a synchrotron radiation source. The microscopic residual stress distributions in the laser single pulse irradiated area and the laser single line irradiated area were also measured using synchrotron radiation in order to clarify the residual stress generation process. Compressive residual stresses are observed in the surface and inner part near the surface after the two dimensional laser peening process, which covers certain area by repeating the single line irradiation. The stress value depends on the scanning direction of laser peening, that is, the stress in the direction of laser scanning is smaller than that in the perpendicular direction. On the other hand, tensile residual stresses were observed in a laser single pulse irradiated area. The value of residual stress in surface gradually changed to the compression side, when the number of laser pulses per unit area or unit length was increased.

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The Compliance Method (CM) was implemented in its fracture mechanics variant to measure residual stress distributions. The method was applied to measure the residual stress distribution introduced in a Compact Tension (CT) specimen by a loading cycle. The stress distribution was also estimated by modeling the loading cycle by using an elastic-plastic Finite Element Analysis. Further, ten strain gauge measurements were carried out along the cutting line to estimate stresses locally. Good agreement between the three procedures was observed. Besides, ability of the method to des cribe residual stress redistributions and releases as a function of crack extension was analyzed.

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Fundamental study for the history of thermal stress due to phase transformation and residual stress during welding heat cycles is studied in order to investigate the generating mechanism of residual stress and the effects of material properties on stress generation. Two materials of high-tensile strength steels are used in the numerical simulation and heat cycle experiment. Both-ends fixed bar specimen is received a simulated welding heat cycle in the apparatus. Material property of each microstructural phase is used and the time- and temperature-dependant proportion of microstructure are considered by using CCT-diagram in the numerical analysis. Thermal stress history obtained by the simulation agrees well with the experimental result during welding heat cycles.

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Optimization of the rapid X-ray stress measurement method and its condition on large grain austenitic tube steel using a Kα line has been investigated. X-ray residual stress measurements were conducted using several Kα, lines on several surface conditions of large grain austenitic tube steel. Using the VKα, line, the measurement time can be reduced to one third compared to the CrKβ line. For a rapid measurement, a superimposing procedure of the X-ray diffraction profile from different incident beam angles (superimpose oscillation method) was also employed achieving a similar effect to that of incident beam oscillation. The best measurement condition was discussed using the above superimpose oscillation method that is an effective method for material with a large grain size.

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Thermal barrier coatings (TBCs) of 8wt% yttria-zirconia were made by air plasma-spraying (APS) and by low-pressure plasma-spraying (LPS). TBCs were removed from substrates, and the specimens were prepared as free-standing thin films. The mechanical and X-ray elastic constants were measured under both tensile and bending deformations, where a specially designed jig was used for tensile tests. The value of the mechanical Young's modulus of APS films measured by tensile loading was close to that by bending. On the other hand, the value of mechanical Young's modulus of LPS films measured by bending was nearly half of that by tensile loading. The difference in the mechanical elastic constant between APS and LPS films were mainly comes from the difference in lamella structures. The X-ray elastic constants determined for both films were nearly identical, independent of the deformation mode. Using the measured values of X-ray elastic constants, the residual stress distribution of TBCs with the substrate was determined.

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The in-depth distribution of residual stresses in shot-peened steels was measured by using high energy X-rays from a synchrotron radiation source. The relation between the 2θ and sin^2ψ was obtained with the side-inclination method (ψ diffractometer). The measurement was carried out for as shot-peened and buffed specimens. The distribution of residual stresses was first evaluated by the nonlinearity of the sin^2ψ diagram by a simplex method. The influence of the roughness of the specimen surface on an analysis of the nonlinearlity was significantly large. The estimated stress agreed with the distribution determined through the sin^2ψ method by using Cr-Kα radiation combined with the conventional surface removal method. A new method was proposed to estimate the distribution of the residual stress. The new method was a combination of the side-inclination method and the iso-inclination method (ω diffractometer) to maintain the penetration depth constant. The sin^2ψ diagram could be approximated by the linear relationship in a wide range of sin^2ψ. The evaluated stress distribution agreed well with the distribution obtained by the surface removal method.

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Titanium nitride (TiN) thin films were deposited by the ion beam mixing (IBM) on the steel substrate. TiN thin films had a fiber texture with the fiber axis of <001> direction perpendicular to the film surface and the film thicknesses were 0.5, 1.0, 2.0, 4.0μm. These specimens were subjected to four point bending, and the stresses in films and substrates were measured by the X-ray diffraction method at each applied strain. In the examination, the films surface were replicated with cellulose acetate sheets at each applied strain and the replicated sheets were observed by scanning electron microscopy. The initial residual stress was equi-biaxial compression between -3.0, -2.7, -2.3, -0.9 GPa for the cases of 0.5, 1.0, 2.0 and 4.0μm, respectively. For thinner specimens, the rate of the increase of measured value of σ_<11> with the applied strain is lower than that of prediction, while for the film with 4.0μm the experimental value agrees well with the prediction. While the substrate is under uniaxial stresses, the film was in the biaxial state of stress because of the mismatch of Poisson's ratio. When the measured stress in the film exceeds a certain value, the stress departs from the linear relation and levels off. The onset of nonlinearity is slightly after the first appearance of cracks and the leveling of the stress was caused by multiple cracks in the film. The maximum stress measured in films increased with decreasing thickness.

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Residual stress was generated in several structural ceramics by sintering and grinding, then estimated using the Vickers indentation method. First, we sought the most appropriate pretreatment for measuring fracture toughness (basis value, K_C), while preventing any influence from residual stress. This is important in estimating residual stress using the Vickers indentation method. Based on that value, the residual stress in Al_2O_3 and Si_3N_4 ceramics was estimated by the Vickers indentation method. Next, several problems in using the indentation method on ZrO_2 ceramics were discussed, focusing on phase transformation. Residual stress in Al_2O_3 and Si_3N_4 was nearly eliminated by annealing the specimen after hand grinding. Consequently, this treatment method is considered effective for determining the basis value K_C . The estimated residual stress value in Al_2O_3 and Si_3N_4 obtained by the Vickers indentation method at 98N corresponded closely to the values obtained by the X-ray method. The value for ZrO_2, however, was larger than that found by the X-ray method. This difference is assumed to derive from phase transformation.

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The surface compositions and morphologies of pure chromium after wet polishing, air oxidation and further micro-wetting by distilled water, were investigated with X-ray photoelectron spectroscopy (XPS) and the AC non-contact mode of atomic force microscope (AFM). An organic contaminants/water film on the chromium oxide/hydroxide layer, was detected by XPS analysis for each surface. The oxide/hydroxide layer became thicker, and the oxide : hydroxide ratio increased, after air oxidation. In ambient air, the AFM showed a thin liquid film on each surface, which was easily moved by the cantilever of the AFM and can be condensed or evaporated. The inner part of the liquid might be adsorbed water, and the outer part is thought to be organic contaminants since the liquid did not combine with distilled water applied by post-wetting. Micro-droplets of distilled water deposited by post-wetting always occupied positions with little or no liquid, which might explain the obtained higher micro- than macro-wettability.

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