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Volume 32, Issue 8
Displaying 1-21 of 21 articles from this issue
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Masami Yajima, Mitsuru Ishii1968 Volume 32 Issue 8 Pages 697-701
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSObservations by transmission electron microscopy on the pressurized iron thin foils have confirmed that the density of dislocations increases in the region near the particles of second phase upon hydrostatic pressure exposure at 10 or 14 kb. These pressure-induced dislocations are observed around FeO particles of several microns in diameter but not around the small carbides (size effect). These observations are in agreement with the following experimental results. (1) The most significant pressure effect, i.e. the lowering of yield stress and the decrease of the Lüders elongation are found for iron containing 600 ppm O2 but no effects are found for a zone refined iron the oxygen content of which is 68 ppm. (2) The pressure effect on iron containing 200 ppm O2 is not prominent, although the iron contains a great number of fine carbide particles.
The shear stress arising from the surface of inclusions by the volume indentation effect under a pressure of several thousand atmospheres is about one hundredth of the stress to nucleate dislocations, which leads to the conclusion that pressurization unpins old dislocations and multiplicates them around large inclusions.View full abstractDownload PDF (2718K) -
Shozo Yoshioka, Yutaka Nakayama, Norio Hosokawa, Kenya Nakai1968 Volume 32 Issue 8 Pages 702-708
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe size, shape and density of intermediate α′ phase precipitates in Al-Zn alloys aged at high temperatures have been studied by mean of transmission electron microscopy as a function of aging time.
The reverted condition was detected in this alloy i.e., G.P.zones dissolved by aging at 150°C for 6 min, while the secondary defects completely annealed out at 150°C for 1 hr.
After aging at 150°C for 1 hr, the formation of plate-like α′ phase precipitates parallel to {111} planes began to occur. The density of the plate like α′ phase precipitates increased gradually with increasing aging time and reached a maximum after 20 hr-aging, and the size of them continued to increase.
The shape of α′ phase precipitates changed from plate-like to parallelopiped after 100 hr-aging. During the growth of parallelopiped α′ phase precipitates, a few dislocations generated around of them. Finally α′ phase precipitates changed their shape from parallelopiped to columnor.
It was observed that the high yield stress obtained with the alloy containing the plate-like α′ phase precipitate and the variation in the yield stress during the aging was consistent with that in the density of the plate-like α′ phase with aging time.View full abstractDownload PDF (3250K) -
Tomitaka Nishimura1968 Volume 32 Issue 8 Pages 708-713
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe author has studied on the changes in hardness, tensile properties, electrical resistivity, lattice parameter of matrix, carbide reaction, and electron microstracture of 0.3C-3Mo-Cr type steels containing 2∼12%Cr when they were isothermally tempered in the temperature range of 400°∼700°C up to 1000 hr.
The results obtaind were plotted against the tempering parameter P=T(20+logt)×10−3, and discussed. In higher Cr steels, the peak of hardness shifts to the lower parameter side. In the process of softening an abnormal change occurs, and the elongation and reduction of area decrease suddenly. The electrical resistivity and lattice parameter of matrix decrease with increase in the tempering parameter, and show larger values in higher Cr steels. On isothermal tempering, the following reaction in carbides takes place: Fe3C→M2C→M7C3+M6C for 2%Cr steel, and Fe3C→M2C→M23C6+M6C for 5∼12%Cr steels. In higher Cr steels, iron carbide transforms more rapidly to alloy carbide, and the rate of growth and the agglomeration of alloy carbide becomes smaller.View full abstractDownload PDF (2356K) -
Shigeo Zaima, Masamichi Hirono1968 Volume 32 Issue 8 Pages 714-720
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe cast alloys of the Al-Zn-Mg system have actively been studied because of their good mechanical properties, age-hardenability, anti-corrosion property, weldability and machinability. In this paper, the mechanical properties, especially, the machinability in turning relating to cutting resistance, surface roughness, tool wear, chip treatment, etc. were discussed on Al-4Zn-5Mg alloy and Al-3Zn-3.5Mg alloy containing larger amounts of magnesium than usual alloys now under development. As a result, new alloys showed good mechanical properties as high-strength alloys, and their values of cutting resistance on the same plane were almost equivalent to those of lautal whose cutting resistance is an average of aluminium alloys, and they showed a rather good surface, with no particular problem in turning. But when the cutting speed was raised more than about 500 m/min, the cutting temperature increased to the proximity of the melting point of the cutting material, and the fusing deposits adhered to the tool flank, resulting in a defective surface. The tool wear was less than 50% of that of Lo-ex, and the chip treatment seemed to be fairly satisfactory.View full abstractDownload PDF (2900K) -
Diffusion Layers between Carbon Steels and Cemented Carbides Containing Tantalum or Titanium CarbideHisashi Suzuki, Takaharu Yamamoto, Ichiro Kawakatsu1968 Volume 32 Issue 8 Pages 721-725
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe addition of tantalum or titanium carbide to WC-Co cemented carbide has been known to depress the cratering wear on the carbide tools during cutting steel. In order to obtain some fundamental information on this cause, carbon steels and three-phase cemented carbides containing tantalum or titanium carbide were mutually welded at 1250°C for 1 hr, and the diffusion layers were examined. Main results obtained were as follows:
(1) The characteristics of the diffusion layers developed between carbon steels and cemented carbide specimens were the same as those between carbon steels and WC-Co straight alloys. For example, the structure of the layers was strongly affected by the carbon content of each coupling material, and the M6C type compound was formed only when the low carbon cemented carbides were coupled with low carbon steels.
(2) Tantalum carbide and β phases were stable in the diffusion layers, and these carbides checked not only the diffusing amount of cobalt and iron but also the formation of the M6C type compound. The formation of the complex carbide was highly supressed by titanium carbide addition.
(3) Tantalum carbide and β phases in cemented carbides changed their carbon contents according to the inter-diffusion of carbon, suggesting that these carbides acted as sinks or source of carbon. Thus, it was considered that this mechanism was closely related to the suppressing effect of carbide addition on the formation of the complex carbide or in practice on the cratering wear of carbide tools. The reason why titanium carbide is more effective to the reduction of cratering wear than tantalum carbide was discussed in detail.View full abstractDownload PDF (1665K) -
Kiyokazu Ogawa, Kiyomitsu Otomo1968 Volume 32 Issue 8 Pages 725-730
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSGas carburization by a drip feed method is carried out by directly introducing an easily decomposable, organic liquid which such as methanol into a furnace. In this report the decomposing condition of the liquid, gas composition and carbon potential of an atmosphere produced with the decomposition of methanol are discussed. The results obtained are as follows:
(1) The gas composition, dew point and carbon potential of the atmosphere was related to the drip speed of the liquid, and their equilibrium was attained at a specific drip speed.
(2) The sufficient carburization of a steel was obtained by the atmosphere produced from methanol alone.
(3) Addition of water to methanol was effective for the prevention of sooting and for the control of carbon potential.
(4) Carbon potential of the atmosphere can possibly be controlled by its dew point and gas composition.View full abstractDownload PDF (2012K) -
Masataka Sugiyama, Tatsuichi Fukusako, Akira Sato1968 Volume 32 Issue 8 Pages 731-735
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRegarding the direct-rolling prosess of molten metals for the continuous production of finished products directly from molten metals as a developed method of continuous casting, an attempt was made to study the manufacturing condition of semi-finished products by this method. Direct-rolling of molten metals by a laboratory machine (with Bessemer’s twin-rolls system) was carried out on the pure aluminium which has a high elasticity and is characterized by solidification of the skin formation type. The main results on the manufactuning conditions and mechanical properties were as follows: (1) Relations between the pouring temperature of the molten Al and the direct-rolling speed showed that for the pouring temperatures of 680°, 700°, 750°C, the upper limit of direct-rolling speed was 750, 650, 630 mm/min, respectively and its lower limit 630, 550, 500 mm/min, respectively. (2) When the cooling capacity of the main rolls was great enough and when the direct-rolling speed was slow, the molten aluminum was solidified before reaching the minimum space of main rolls. (3) The cooling effect of the main rolls was very great in direct-rolling because of good contact between the surface of the main rolls and the solidified aluminium. (4) The tensile strength, elongation and hardness of the surface of the direct-rolled plates increased as the direct-rolling speed decreased. This was because that rolling was done by the main rolls. (5) In the application of direct-rolling of the molten pure aluminium, the use of secondary water spray cooling was derisable and the use of the front-tension should be avoided.View full abstractDownload PDF (1885K) -
Ichiro Morimoto, Mitsunori Sato, Masayuki Hijikata1968 Volume 32 Issue 8 Pages 736-741
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe transfer of metal from anode to cathode of electrical contacts has been measured in a range of applied voltages from 2 to 8 volts and of circuit currents from 1 to 45 amperes in argon atmosphere. Results obtained are as follows. The material transfer is given approximately by an empirical formula as W = KM(1-E_r/E)^2 I^2/T_m, where W is the amount of metals transfered in milligram per operation, K is a constant and 2.5×10−7, M is the mean atomic weight, Tm is the melting temperature in degrees Kelvin, Er is the bridge voltage at rupture in volts and is equal to 6.9×10−4Tm, E is the applied voltage in volts and I is the circuit current in amperes.
This relationship may hold under the following condition: 6V≥E>Er and I>Imin⁄(1−Er⁄E), where Imin is the minimum current necessary for a permanent arc.
The main cause of the material transfer in light duty contacts is considered to be the short arc energy depending on the lowest value of inductance when the bridge is ruptured, and the material transfer is little influenced by the thermoelectric effect.View full abstractDownload PDF (2074K) -
Isao Gokyu, Keijiro Suzuki, Chozo Fujikura1968 Volume 32 Issue 8 Pages 742-745
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA number of workers have discussed the validity of using the r-value to predict the drawability of sheet metals. In low carbon steel sheets, the r-value is known empirically to provide a useful criterion of the drawability, but in fcc alloys, such as 18-8 stainless steel, nickel silver and α-brass, the r-value cannot be used as a useful criterion because of the weak dependence of the drawability on the crystallographic texture. For example, in nickel silver and α-brass sheets the conical cup values remain constant with increase in the (225)[73\={4}] orientation component, though the r-value becomes higher. So there remains some doubt whether high r-value improves the ability to undergo deep drawing operation.
Deep drawing of aluminum single crystal sheets was done by the single blank load method in order to study the drawability of sheets with various orientations.
The results obtained are as follows:
(1) Plastic strain ratio r should be considered in terms of the resistance of deformation in the flange.
(2) Sheets have good drawability when the (111) or (110) plane is orientated parallel to the sheet plane, the former being slightly better. The sheet with the (100) orientation has poor drawability.
(3) The preference in (225)[73\={4}] orientation makes the r-value higher and the deformation strength in the flange part lower, and reduces the fracture load in the wall. Therefore, it can be predicted that this orientation makes little contribution to the deep drawability.View full abstractDownload PDF (768K) -
Mutsuo Ichihara, Seiichi Kakuwa1968 Volume 32 Issue 8 Pages 745-751
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt was made clear in the previous report that the concentration of alloy elements such as Mn and Cr occurred on the uppermost surface of the steel material by gas carburizing and that the concentration was caused by internal oxidation resulting from the carburizing gas atmosphere. Studies were made this time by X-ray fluorescence analysis and electron micro probe X-ray analysis to see the effects occurring on the behaviours of Mn and Cr at the surface when the gas atmosphere was varied within a wide range from carburizing to decarburizing.
The results showed that as the carburizing potential of the atmosphere became greater the amounts of Mn and Cr on the surface also increased. In the decarburizing atmosphere the concentration of Mn and Cr was not seen on the surface, but the peaks Mn and Cr which were lower than those in the carburizing atmosphere occurred at approximately 10 μ below the surface. This shows that there is some difference in mechanism between the internal oxidation in the carburizing atmosphere and that in the decarburizing atmosphere. In the case of the carburizing atmosphere, it may be explained that a selective oxidation of metals was caused by CO, CO2 partial gas pressure. In the case of the decarburizing atmosphere, a uniform layer of internal oxidation was formed by the sufficiently high oxygen potential and this is presumed to be the reason why the peaks of Mn and Cr were not seen on the surface.View full abstractDownload PDF (2740K) -
Hiroyasu Mitani, Hiroshi Nagai1968 Volume 32 Issue 8 Pages 752-755
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAlthough several reports have been published in regard to the subhalide reaction between Al and AlCl3, very little has been reported about the influence of impurities in crude aluminum alloys on this reaction. Moreover, in the investigation of the reactivity between AlCl3 and crude Al alloys, the knowledge of activities of Al in these alloys is indispensable. However, the determination of the activities in Al alloys was limited, for instance, much of the activities in the liquid Al-Fe system remain unknown because of the high liquidus temperatures and the complexity of the solid-state reactions.
In the preceding study, the reactivity between AlCl3 and liquid Al-Si binary alloys was investigated by the bubbling method, and then the activities of Al and Si in these alloys were determined.
In this report, the reactivity between AlCl3 and liquid Al-Fe binary alloys in the composition range NFe<0.339 was investigated by the same method described previously. Combining the equilibrium constant determined previously with the experimental data on liquid Al-Fe alloys, the activities of Al in these alloys were determined at 1100° and 1200°C. The activities of Al in these alloys show a strong negative deviation from Raoult’s law below 84.5 at%Al. The activity curve is found to be similar in shape to those calculated by using a regular solution theory and the equation derived by Hauffe and Wagner.View full abstractDownload PDF (955K) -
Masakazu Miyagi, Masaki Morikawa, Shigeo Shin1968 Volume 32 Issue 8 Pages 756-761
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSeveral workers(1)∼(5) have made crystallographic studies of ω phase in titanium alloys. Austin et al(1) and Frost et al(2) have reported that the ω phase is bcc with edge length three times that of the basic bcc cell. Silcock(3) and Bagaryatskii et al(4) have independently proposed a hexagonal structure oriented with respect to the β cell. An attempt was made to clarify the true ω structure. For this aim, a single crystal X-ray analysis has been carried out by using Ti-8.2%Mn and Ti-14.1%Mo alloys, and the precipitation in the Ti-Mo alloy has been observed by transmission electron microscopy. The results obtained are summarized as follows: (1) The Laue photographs obtained from aged crystals showed cubic Laue symmetry. As a result of detailed intensity measurements, it was comfirmed that the true ω structure is the hexagonal cell which has four orientations in each β cell with the relationship [111]β||[0001]ω; [1\bar10]β||[1\bar210]ω as proposed by Silcock. In this experiment, no reflection was observed from the relpoints of which calculated structure factors are equal to zero. Therefore, there is no need to consider the rampling plane proposed by Bagaryatskii et al, that is, the atomic positions may be 0 0 0; 1/3 2/3 1/2; 2/3 1/3 1/2 rather than 0 0 0; 1/3 2/3 0.48; 2/3 1/3 0.52. (3) As a result of transmission electron microscopic observation, it was found that the shape of ω particles is ellipsoidal. The major axis of the ellipsoid may be parallel to the ⟨111⟩β directions and oriented with four orientations.View full abstractDownload PDF (2055K) -
Kin’ichi Hasegawa, Makoto Terajima1968 Volume 32 Issue 8 Pages 761-766
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUse of germanium coated substrates remarkably improves magnetic properties and the reproducibility of electrodeposited permalloy thin films used as high speed memories. Effective features of the germanium coated substrate (germanium/silver/glass) were examined in comparison with silver substrates (silver/glass and silver/germanium/silver/glass), using a B-H loop tracer, an electron microscope and an X-ray diffractometer. The results are as follows;
(1) The crystallite size of the electrodeposited permalloy thin film increases with increasing crystallite size of the substrate.
(2) Surface roughness of each substrate is of nearly the same order of magnitude.
(3) The magnetic properties of the permalloy film (with zero average magnetostriction and a thickness of 1000 Å) deteriorate with increasing crystallite size of the permalloy film.
(4) Consequently it is suggested that the advantage of germanium coated substrates arises from their amorphous structure.View full abstractDownload PDF (1439K) -
Toshiya Wada, Fumio Matsumoto, Katsuro Kuroki1968 Volume 32 Issue 8 Pages 767-773
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMany works have been done on the behavior of 3%Si-Fe (001)[110] crystal on annealing after cold rolling, but a clear-cut conclusion has not yet been reached. To clarify the recrystallization behavior of this crystal the experiment was done on specimens of various sizes and by rolling under various conditions and annealing at such high temperature as 1200°C.
The results are summarized as follows:
(1) 3%Si-Fe (001)[110] crystal, with a sufficiently large size, which was carefully rolled 70% and its edges were trimmed after cold rolling, did not recrystallize on annealing 20 hrs at 1200°C.
(2) When the crystal was recrystallized on annealing, the recrystallization nucleus seems to have been formed by the slip other than probable active slips. These slips were caused by either the size effect of specimens or by rolling conditions.
(3) When (001)[110] crystal did not recrystallize on annealing, only the recovered state having large subgrains and dislocation net works were observed. The initial (001)[110] orientation was substantially maintained through cold rolling and high temperature annealing.View full abstractDownload PDF (3034K) -
\={O}hiko Kammori, Isamu Taguchi, Yasushi Ariura, Ken-ichi Takimoto1968 Volume 32 Issue 8 Pages 773-778
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe oxide inclusions of the sample from the core center of the rimmed steel ingot were quantitatively isolated without damage on the shape by means of the ultrasonic stirring-extraction method (19.3 kc, 60°C) using I2-methyl alcohol solution containing sodium methylate. The isolated inclusions were successfully classified according to the size by the ultrasonic screening apparatus fitted with 120 μ, 70 μ, 35 μ and 7 μ sieves. The classified inclusions were analyzed by spectrophotometry and atomic absorption spectrophotometry, and also studied by means of microphotoscopy and X-ray diffraction.
The main oxide components of the inclusions of the sample were found to be silicon oxide (SiO2), aluminum oxide (Al2O3), iron oxide (FeO) and manganese oxide (MnO). Their percentages in each inclusion group classified according to the size were varied depending on the inclusion size. The percentage of silicon oxide and aluminum oxide increased but that of iron oxide decreased, as the inclusion size grew larger. However, that of manganese oxide remained almost constant.
A nickel-electroplating method of preparing 7 μ sieve from 20 μ copper sieve is also described.View full abstractDownload PDF (2228K) -
\={O}hiko Kammori, Naoharu Yamaguchi, Kimitaka Sato, Fumio Kurosawa1968 Volume 32 Issue 8 Pages 779-784
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn infrared spectrometric method was developed for the quantitative analysis of trace amounts of boron nitride (BN) in the residues extracted with sulphuric acid from steel samples. After the extracted residues collected on the Millipore filter (100 mμ) were transferred into 300 mg of potassium bromide powder with Johnson’s method, the transmission spectra were measured using the disk prepared. A quantitative estimation was tried by using the specific absorption band in the infrared absorption spectra of residues. The results obtained are as follows:
(1) Twenty minutes were proper as the time for pulverizing and mixing potassium bromide powder and the residues in the agate mortar.
(2) When more than about 150 μg of carbon was contained in 300 mg of potassium bromide powder, it was impossible to detect the absorption band of samples.
(3) Calibration curves were drawn up with the base line method. 1383 cm−1 and 819 cm−1 bands were employed for 3∼30 μg and 30∼120 μg of boron nitride (BN), respectively, and 1085 cm−1 band was also done for 0.1∼1.1 mg of boron carbide (B4C). The absorbance,log(I0⁄I), and the quantity of boron nitride or boron carbide were linearly correlated.
(4) Ten kinds of the standard mixing samples were precisely determined.
(5) It was found that the quantity of total nitrogen (N) in steel is correlated to N×b⁄(a−c), where a is the quantity of insoluble boron in steel, b is the boron content in boron nitride determined by means of infrared spectrometric method and c is the boron content in the residues remained in the meshes of the Millipore filter.View full abstractDownload PDF (1616K) -
Ishi Miura, Hitoshi Hamanaka1968 Volume 32 Issue 8 Pages 784-789
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUnidirectional solidification of eutectics offers a simple, inexpensive approach to the production of composite materials. The authors and co-workers have studied the production of fiber strengthening composite materials by various methods. In this paper, an attempt has been made to prepare Al-Si eutectic fibrous composites by means of unidirectional solidification. The main results are follows:
(1) In order to produce continuous structures of Al-Si eutectic alloys, it was found that solidification rate was less than 1.5 mm/hr by using four or five nine aluminum and semi-conductor-grade silicon as materials.
(2) The cross section of silicon colonies showed four-fold symmetry and side branching, and individual silicon colonies extended over several millimeters in the growth direction. Wavy patterns of silicon phase were observed among straight silicon colonies in a cross section parallel to the growth direction.
(3) The growth mechanism of Al-Si eutectics seemed to differ from that of lamellar and rod-like structures, as silicon had a highly preferred growth direction. So the two phases did not exhibit any consistent orientation relationship.
(4) Impurities of materials have a considerable effect on the growth of silicon phases. So, if the factors which effect the growth of silicon phases is found, the shape of silicon colonies may be controlled, for example, by adding the third element to Al-Si eutectics.View full abstractDownload PDF (3063K) -
Takashi Sakaki1968 Volume 32 Issue 8 Pages 790-796
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn experiment was carried out to establish a simple and accurate method for the determination of niobium in high alloy steel.
The niobium was separated as pentaoxide from other elements by the hydrolysis method with sodium sulfite and tannic acid, and the separated niobium was determined by the spectrophotometric method with xylenol orange. This spectrophotometric method is not affected by the presence of 0.1 mg of chromium, 0.2 mg of cobalt, 1 mg each of antimony, manganese, tantalum and tin, 20 mg of molybdenum, 10 mg of titanium and 60 mg of tungsten are contained in the separated sample solution. The precence of aluminum, bismuth, copper, iron, nickel, vanadium and zirconium is found to interfer with the spectrophotometric method. However, this interference can be eliminated by the use of EDTA.
As a result of the experiment, the author succeeded in establishing a method in which 0.02 to 6% of niobium in high alloy steel can precisely be measured without difficulty.
The niobium contents in synthetic and actual samples were measured by this method with satisfactory results.View full abstractDownload PDF (2068K) -
Tetsuya Takaai1968 Volume 32 Issue 8 Pages 796-802
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe metallographic features of the cast structures of electron-beam melted Nb alloy ingots were examined mainly by microscopic observation, autoradiograph, X-ray microanalysis and X-ray diffraction analysis. Contrary to expectation, the cast structure of the ingots consisted of equi-axed grains and the beta solid solution was retained at room temperature.
Micro segregation of zirconium was noticed at grain boundaries and inside the equi-axed grains, forming a subgrain boundary-like structure. According to X-ray microanalysis, the estimated zirconium concentration of the segregated zone was nearly equal to the concentration of the final liquid in the freezing process of the alloys. Zirconium was also segregated macroscopically to the outer surface of the ingot, forming sharp inverse segregation. The principal cause of the inverse segregation was attributed to the effect of outgassing pressure on the zirconium rich melt in the freezing transient layer.View full abstractDownload PDF (2487K) -
Tetsuya Takaai1968 Volume 32 Issue 8 Pages 802-807
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDuctility of electron beam melted Nb alloy ingots was studied mainly by the Charpy impact test and the tensile test.
Marked differences of room temperature ductility between Nb-Zr (NZ) alloy ingot and Nb-Zr-Ti (NZT) alloy ingot were observed. That is, the NZ alloy fractured in a brittle manner at room temperature contrary to the ductile fracture of the NZT alloy ingot and repeated twin formation was noticed for only the NZT alloy ingot during the tensile test. The transition temperature of the NZ alloy ingot due to the Charpy impact test was about 250°C and 250°∼330°C higher than the NZT alloy ingot.
The room temperature ductility of Nb-Zr alloy ingot was influenced strongly by the zirconium concentration and an abnormal brittle fracture was observed for only the Nb-30%Zr alloy ingot, while there was no remarkable correlation between the O2 gas content and the ingot ductility, and titanium was assumed to be equivalent to zirconium.View full abstractDownload PDF (2245K) -
Katsuya Watanabe, Akinori Katsui1968 Volume 32 Issue 8 Pages 808
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (114K)
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