The equilibrium phase diagram for the CdTe-Ge system has been determined by means of differential thermal analysis, X-ray diffraction and microscopic examination.
This system can be considered as a pseudobinary system from the result of X-ray experiment. There is no intermediate phase except CdTe and Ge phases in any composition. Mutual solid solubility of CdTe and Ge could not be detected by X-ray analysis. The monotectic temperature lies at 1342 K and the region of the liquid immissibility at this temperature is given as the composition of 6.5∼93 mol% Ge. The eutectic point lies at 97.5 mol% Ge and 1199 K.

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Effects of microstructures obtained by two kinds of thermomechanical treatment, i) solution treatment-cold rolling (67%)-aging and ii) solution treatment-aging-cold rolling (67%), on the fatigue behavior of an Al-1.8wt%Li alloy were investigated by means of optical and transmission electron microscopy. The results obtained are summarized as follows:
Deformation bands perpendicular to the rolling direction were formed inhomogeniously in the cold-rolled specimens, and the dislocation cell structure and microbands were the characteristic features. Fatigue strength in both the thermomechanically-treated specimens was higher than those in the solution-treated specimens, in the solution-treated and cold-rolled specimens and in the aged specimens. The higher fatigue strength is due to the dislocation cell structure with δ'-Al₃Li precipitates, because the cell structure alleviates the concentration of dislocation on a slip plane during fatigue test.
Fatigue strength in the specimens with the deformation bands parallel to the axis of fatigue stress was higher than that in the specimens with deformation bands perpendicular to the axis of fatigue stress. The deformation bands perpendicular to the axis of fatigue stress became preferential nucleation sites and propagation path of fatigue cracks. The thermomechanical treatment, i) brought out higher fatigue strength than the treatment, ii).

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Recovery and recrystallization processes of pure silver and its alloys containing about 0.1 at % of cadmium, tin or antimony deformed 40∼90% by rolling at-196∼60°C were examined by micro-Vickers hardness and electrical resistivity measurements.
The recrystallization temperature of these alloys decreased with increasing area reduction and with lowering deformation temperature. The solute elements which have large binding energy with atomic vacancies raised the recrystallization temperature of silver, because they trap atomic vacancies and inhibit their migration.
When the kind and the quantity of the solute elements were fixed, Δρ_E/Δρ_W was shown to be almostly constant independent of the degree and the temperature of deformation, where Δρ_W and Δρ_E are the increment of specific resistivity by the plastic deformation and the decrement of it by the recovery process, respectively. For a definite deformation condition, the recrystallization temperature of the alloy increased with increasing Δρ_E/Δρ_W.

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The discontinuous precipitation process of Mg–Al alloys during aging has been investigated by metallographic observation. In Mg–Al alloys, the initial stage of discontinuous precipitation cell formation had preferential precipitation and local instability of the grain boundary. With continued aging, the local migration of the original grain boundary rose into the adjacent grain. Consequently a solute depleted region was formed behind the advancing grain boundary. After a while, the preproposed S-mechanism required for the formation of double seam morphology appeared. The occurrence of both single seam and double seam morphologies were conformed at both aging temperatures lower and higher than T_m/2 (T_m: melting temperature). These facts do not coincide with Baumann's assumption that the highest dependence is on aging temperature. After the solution treatment, a Mg–9.5Al specimen was cold compressed by 3.2∼15.3%. The cold work prior to aging does introduce additional nucleation sites for general precipitation, with the age hardening somewhat accelerated. The fractional area of discontinuous precipitation cells was suppressed by the deformation twins, only onset of cell formation increased the rate.

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A new criterion for the initiation of dynamic recrystallization is proposed. The criterion, Z_c is the critical value of the Zener-Hollomon parameter when the dynamic recrystallization can initiate. The specimens used in this investigation were the sheets of copper alloys containing 0.1at% each of Ga, Ge, Al, Sn or Au. The Z_c decreased by the addition of elements in this order: Ga, Ge, Al, Au and Sn. It is shown that an additional element, which raises static recrystallization temperature, also suppresses dynamic recrystallization.

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Interrelation between superplastic deformation and internal friction was investigated using an Al-Cu eutectic alloy. The increment of internal friction at room temperature due to deformation, ΔQ^-1, increased with the amount of strain under non-superplastic deformation conditions, while under superplastic conditions the change in ΔQ^-1 was relatively small. Strain amplitude dependence was observed in ΔQ^-1 of specimens deformed at lower temperatures or higher strains. An analysis of the strain amplitude dependent internal friction was carried out by using Granato-Lücke theory. It was found that ΔQ^-1 was proportional to the dislocation density ∧. It was also found that the strain rate sensitivity of flow stress m (σ=k^εm, σ: flow stress, ε: strain rate, k: constant) was proportional to the negative value of ΔQ^-1 or ∧. Changing characteristics of ΔQ^-1 for various strains and deformation conditions showed a good correspondence to the results of the direct observation of dislocation structures.
These results are consistent with the superplastic deformation mechanism proposed previously, which involves the grain boundary sliding compensated by the diffusional process predominantly and the dislocation motion acting to decrease the m value.

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軽焼マグネシア系土壌硬化剤と糊材のスラリーを地表面に薄く散布することによって、降雨等に伴う土壌浸食の防止及び雑草抑制ができる。また、現地土壌と同硬化剤による粒状の成型物を20mmの厚さで敷き均すことによっても浸食を防止できる。

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The distribution of three dimensional grain size has been directry measured during grain growth of pure aluminum by the special method of separating and weighing individual grains, which was used by Rhines and Patterson. It is concluded in consideration for the limit of measurabilitiy that the observed grain size distribution is approximately log normal for all specimens, and its spread does not vary remarkably during grain growth in this experiment. The grain size distribution from the computer simulation of grain growth by Exxon group is shown to be closer to the present experimental result than that from the representative theory of grain growth by Hillert, which is attributed to the fact that the former deals with growth or shrinkage of the individual grains while the latter growth of an isolated grain in an average environment.

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Using the model samples (Fig. 1 and 2) as the two phase alloys which joined by fusion with the various plugs in the annealed square copper bar, the effects of the second phase due to rolling on the deformation of the matrix round of those phases were observed. From the experiments, the following results were summarized;
In the specimens consisting of a softer or harder second, phase with the matrix, in general, a softer second phase undergoes greater deformation than the matrix and a harder one tends to deform less than the matrix. The flow line of the matrix round a second phase is disturbed remarkably and degree of the disturbance have reference to the difference of the deformation of the both phases. The region of disturbance of the material are not depend on relative hardness of the both phases and increasing of average percentage reduction of the test-piece, but affected on the size of the each second phase.

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Strengthening due to the thermo-mechanical treatment (TMT) was examined in the polycrystalline Cu-7.5at%Ni-2.5at%Al alloy. Specimens were solution treated, aged, cold rolled and finally aged. It was found that their mechanical properties were much improved not only at room temperature but at high temperatures up to 500°C, comparing to those simply aged and mechanicothermal treated (MTT: solution treated, cold rolled and finally aged).
Precipitated particles with Ll₂ type ordered structure grown during preageing, were sheared by cold rolling. High density of dislocations was introduced. However, sheared particles played an important role to strengthen the alloy. The first notable effect of TMT is to retard recovery of the cold rolled structure extremely in final ageing. In consequence, the deformed structure was kept after final ageing. The second is the growth of precipitated particles with smaller sized and higher density in final ageing, which were formed from sheared particles and nucleated in the matrix. Excess vacancies introduced by cold rolling would accelerate the growth of particles.
Strengthening in the TMT specimens is considered to be attributed to the random dispersion of a large number of small sized particles and the existence of high density of dislocations.

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A supersaturated Cu-26Ni-8Fe alloy was deformed by cold rolling and the changes occurring on annealing at 750°C have been follovred by hardness testing and optical and electron microscopy observation. It was found that a modulated structure formed prior to recrystallization of a supersaturated solid solution. In the case of the heavily deformed sample, the iron nickel-rich phases grow anywhere including grain boundaries or deformation bands, and the recrystallization can start in the area free of the modulated structure around the coagulated iron nickel-rich phases. Therefore, the recrystallized structure consists of fine equiaxed copper-rich and iron nickel-rich grains termed as the microduplex structure. The structure has a good strength and ductility at room temperature. The structure also has a suitable high temperature stability and so appears capable of undergoing superplastic deformation at 750°C. The strain rate sensitivity index of flow stress m of about 0.5 was obtained and the specimen maintained a relatively fine equiaxed grain structure even after large elongation at 750°C.

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Aging characteristics of Mg-9mass%Al alloy have been investigated by means of hardness measurement and microstructure observation with optical and electron microscopy. Hardness increased by about HV30 with aging time at temperatures between 403-473K. The hardness increase was found to be caused by the continuous and discontinuous precipitation. The TTT diagram for the phase decomposition was determined from the hardness curves, the nose temperature being 523K. The initiation and growth of the grain boundary reaction occur in competition with well-advanced continuous precipitation process. The apparent activation energy for grain boundary reaction is also described.

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Microstuctures of Al-Cr alloys containing Cr up to 10% solidified by various cooling methods and precipitation behavior during aging at 200-600°C of a melt spun Al-2.75%Cr alloy were investigated. No precipitates can be observed in splat quenched Al-10%Cr nor in melt spun Al-2.75% alloys. The hardness of chill cast alloys increases with Cr content up to about 4%. Electrical resistivity of the melt spun 2.75% Cr alloy shows a two stage sigmoidal recovery during isothermal aging at 200-600°C. Electron microscopy observation of aged samples concludes that the first and the second stages of electrical resistivity change correspond to preferred precipitaion at grain boundaries and within grains, respectively. The size R, half of the length, and S, thickness of the grain boundary precipitated particles during isothermal aging are proportional to tⁿ, where t is isothermal aging time. The time dependent exponent n for R and S are 0.077-0.083 and 0.11-0.17, respectively.

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The influence of dispersions of particles on the recrystallization behavior has been examined in industrially processed specimens of a Cu-Fe-P alloy (CDA194). The specimens are produced through the steps of hot rolling, cold rolling, aging and final cold rolling. The γ→α martensitic transformation of small coherent γ-Fe precipitate particles which form on decreasing temperature during hot rolling is induced by subsequent cold rolling. Aging following the cold rolling produces fine γ-Fe particles, which are transformed to α-Fe by final cold rolling. The nucleation of recrystallization occurs predominantly at coarse Fe₃P particles, observed after the hot rolling, larger than about 1μm in diameter. A denser dispersion of smaller α-Fe particles shows a larger retarding effect on grain-boundary migration. A specimen with smaller α-Fe and smaller Fe₃P particles has a higher heat resistance and a higher strength.

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Influence of grain size and Mg content on the ductility of Al-Mg alloys at 77, 173 and 300K has been investigated. As the grain size increased from 20 to 300μm, the uniform elongation at 77 and 173K reached maxima when grain size was 40μm. On the other hand, at 300K, the uniform elongation increased monotonously with increasing grain size. The local elongation at 300K was nearly constant (3%) regardless of grain size and Mg content, while at 77 and 173K the local elongation increased with decreasing grain size or Mg content and exceeded 10% at 77K when grain size was 20μm. Fractographic observations revealed that the area fraction of intergranular fracture at 77K increased with increasing grain size or Mg content. On the other hand, intergranular fracture was not observed at 177 and 300K regardless of grain size and Mg content. The dependence of elongation upon grain size and Mg content at 77K was explained mainly by the intergranular fracture. Grain size dependence of elongation at 173 and 300K was well explained by the change in both the strain-hardenability and the occurrence of the nonuniform deformation caused by the serrated yielding or the decreased characteristics of the polycrystalline.

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A new method has been proposed for the estimation of the distribution of the three-dimensional grain diameter in a polycrystalline material from the measured distribution of the two-dimensional grain diameter on the cross section of the material. This method has been applied to the estimation of the three-dimensional grain diameter distribution of SUS310S stainless steel during the grain growth. The three-dimensional and the two-dimensional distributions have been compared.
The three-dimensional grain diameter distribution had the larger average value and the smaller variation coefficient, compared with the two-dimensional grain diameter distribution. The activation energy for the grain growth was larger for the analysis of the three-dimensional average grain diameters than for the two-dimensional analysis, and the value was close to those for the grain boundary diffusion of Fe, Cr and Ni.

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Mechanico-thermal treatment (MTT) is one of the effective methods to improve mechanical properties of alloys. In the present study, an improvement in mechanical properties of Cu-7.5 at%Ni-2.5 at%Al alloy by MTT was undertaken in comparison with those of simply aged specimens.
By MTT, hardness, 0.2% proof stress (σ_0.2) and ultimate tensile strength (UTS) have increased at room temperature, and arrived their maximum values by ageing for a remarkable shorter time than those of simply aged specimens. The important point is that σ_0.2, UTS and total elongation are much improved at the elevated temperature as high as 500°C.
To study the origin of strengthening by MTT, thin foils were observed in a transmission electron microscope. In MTT specimens, the deformed structure disappeared perfectly and recrystallized to fine grains by ageing at 500°C for 0.1hr. In contrast with simply aged specimens, very small precipitates were observed within these grains, and the discontinuous precipitates around grain boundaries were scarcely observed. These characteristics in the microstructure would contribute to the strengthening of MTT specimens.

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