巻号一覧
20 巻, 1 号
選択された号の論文の4件中1～4を表示しています
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三谷 裕康1973 年 20 巻 1 号 p. 1-9
発行日: 1973/05/25
公開日: 2009/05/22
ジャーナル フリーIn this experiment it was confirmed that Cu-Al binary mixed compacts were abruptly expanded at the eutectic temperature of 548°C on heating by the exothermic reaction of γ2(Cu9Al4)-formation, and this volume expansion disturbed the following sintering of the compacts.
In order to evade the exothermic reaction above described 50 wt% Cu-50 wt% γ2 pseudobinarv mixed compacts were examined. However, they were also expanded on heating above 600°C by the Kirkendall diffusion (voidformation), and then the influence of Mn, Fe and Ni as an alloying element respectively on the expansion of the pseudobinary compacts were investigated. Results obtained are as follows: The expansion of the compact was increased by Mn-addition, but decreased by Fe-and Ni-addition, where the effect of Ni was superior to Fe far beyond comparison.
Since Ni has the tendency to diffuse selectively in the γ2 phase, difference of intrinsic diffusivities between Cu and Al in the mixed compact seems to be reduced by the selective diffusion of Ni. When Ni-coated Cu particles were combined with the same quantity of γ2 particles, diffusion of Ni should be made easier in the Cu-Ni-γ2 pseudoternary mixed compact, therefore the compact. did not expand abnormally on heating. Consequently the sintered aluminium-bronze of high density could be obtained from the mixed compact of Ni-coated Cu particles and γ2 particles.抄録全体を表示PDF形式でダウンロード (3621K) -
田村 皖司, 宮本 憲治1973 年 20 巻 1 号 p. 10-15
発行日: 1973/05/25
公開日: 2009/05/22
ジャーナル フリーTo attempt a direct production of Cu/Fe clad strips from the powder materials, several factors in the rolling process, by using a newly designed hopper, were investigated, and also mechanical properties of clad strips fabricated in various conditions were examined.
The results obtained were summarized as follows:
(1) With decreasing the tip angle and height of a separator and particle size of powders, the asperities of Cu/Fe strip boundary became smooth.
(2) Because of setting the separator in the hopper, the powder head gave no effect to the thickness and density of strips.
(3) Effects of the roll-speed and roll-gap on the thickness and density of strips were similar to those in the rolling for single powders.
(4) The tensile strength of sintered, cold rolled and annealed strips was of 28 kg/mm2, which was about 6 times as strong as that of the strip as-sintered at 1000°C.抄録全体を表示PDF形式でダウンロード (2033K) -
鈴木 寿, 林 宏爾, 寺田 修1973 年 20 巻 1 号 p. 16-22
発行日: 1973/05/25
公開日: 2009/12/04
ジャーナル フリーMechanical properties such as transverse-rupture strength and hardness of β-(10-20)% Ni alloy with WC up to 8% in β phase were studied, in comparison with those of TiC-Ni, TiC-(15-20)% Mo2C-Ni and β-(15-20)% Mo2C-Ni alloys having the same amount of binder. Four sorts of specimens were in vacuum sintered at various temperatures for 1 hr.
Results obtained were as follows: (1) The grain size of carbide in β-base alloys decreased with increasing WC contents and this decrease appeared to become constant at the WC contents more than about 5 %. In this case, the grain size of β-base alloys was smaller than that of TiC-base alloys generally in the following order; β-Mo2C-Ni<β-Ni<TiC-Mo2C-Ni<TiC-Ni. (2) Anomalous carbide, occluding a plateshaped titanium. carbide, was not observed in β-Mo2C-Ni alloy in contrast to TiC-Mo2C-Ni alloy. (3) The hardness of β-base alloys was naturally increased with increasing WC contents. The hardness of S(5%WC)-Ni alloy was extremely high among others at a definite value of mean free path up to about 0.15 μ. The strength of β(5%WC)-Mo2C-Ni alloy was most excellent at a definite value up to about 0.30.4 μ. Examinations of both strength and hardness of various alloys showed that β-Ni alloy with 5%WC or more was most superior to other alloys, when the hardness above approximately 1500Hv was required. (4) The excellent mechanical properties of β-Ni alloy above mentioned were considered to be partially due to high hardness of β phase, and partially due to high resistance to crack propagation along carbide-carbide interface.抄録全体を表示PDF形式でダウンロード (3888K) -
勝村 祐次, 高津 宗吉, 小堀 景一1973 年 20 巻 1 号 p. 23-29
発行日: 1973/05/25
公開日: 2009/05/22
ジャーナル フリーChanges of ultrasonic attenuation under uniaxial compression have been investigated for WC-Co alloys containing various cobalt contents and grain sizes by means of a conventional ultrasonic apparatus; the measuring frequency was 10 MHz. The attenuation of the alloys plotted against the amount of prestrain began to increase rapidly above some critical strain. This critical strain increased with increasing Co contents and grain sizes of WC. The ratio of the compressive rupture strain (εr) and the critical strain (εc) invariably remained constant, i.e.εr/εc≅4. Microscopic observations showed that the generation of micro-cracks at grain boundaries is responsible for the increase of the attenuation. Under compressive fatigue stresses, the attenuation increased rapidly after a certain number of fatigue cycles prior to the rupture of the alloy.抄録全体を表示PDF形式でダウンロード (4760K)
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