巻号一覧
51 巻, 1 号
選択された号の論文の9件中1～9を表示しています
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今里 州一, 徳本 啓, 坂口 茂也2004 年 51 巻 1 号 p. 3-9
発行日: 2004/01/15
公開日: 2009/12/04
ジャーナル フリーMicrostructures, some mechanical properties and electrochemical corrosive behavior of WC-(0-16)mass% Cr3C2-15 mass% Ni alloys were studied as a function of carbon and Cr3C2 contents of these alloys.
It was found that solid solubility of Cr into γphase (Ni phase) of WC-Cr3C2-15 mass%Ni alloy was about 2% and 4mass% Cr3C2 in high and low carbon alloys, respectively. In the range of the excess Cr3C2 content more than the solubility limit of Cr, some phases of WC+γ+M2C+M6C (θ) (M =(Cr, W, Ni), M6C=θphase), WC+γ+M2C, WC+γ+M2C+M3C2, WC+γ+M3C2 to WC+γ+M3C2+FC appeared with increasing carbon content in the alloys.
Hardness of the alloys increased with increasing the amount of Cr3C2. On the other hand, the transverse rupture strength reached the peak value at the solubility limit of Cr because of the finer grain size of WC by the effect of grain growth inhibition. More than the solubility limit of Cr, the transverse-rupture strength decreased with increasing the amount of Cr3C2, which was considered to be caused by crystallized MxCy acting as fracture source.
On the anodic polarization curve in 3%NaCl solution, corrosive current density of these alloys decreased with increasing the amount of Cr3C2 within the solubility limit of Cr in yphase, but it was saturated more than the solubility limit of Cr.抄録全体を表示PDF形式でダウンロード (2675K) -
久保 雅崇, 伊藤 孝至, 徳田 公平, 単 佳義, 北川 邦行2004 年 51 巻 1 号 p. 10-15
発行日: 2004/01/15
公開日: 2009/05/22
ジャーナル フリーA segmented p-type thermoelectric module of AgSbTe2-(Bi, Sb)2Te3 was fabricated by a Spark Plasma Sintering (SPS) process and its performance was evaluated with both calculations and measurements. Each powder of AgSbTe2 and (Bi, Sb)2Te3 was consolidated by the SPS process. Various temperature distributions in the two-segmented module were simulated by solving an unsteady one-dimensional equation of heat conduction based on the obtained data of thermoelectric properties. An optimum junction point of two elements was predicted from numerical changes in the performances with the connecting position of two materials. Several materials for the electrodes were tested to find better bonding condition between the thermoelectric material and the electrode by SEM-EDX. Finally, the performances of the fabricated module were measured. It was found that the performances predicted by the calculation were in fairly good agreement with the measured ones.抄録全体を表示PDF形式でダウンロード (4512K) -
川崎 亮2004 年 51 巻 1 号 p. 18
発行日: 2004/01/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (91K) -
小林 慶三, 尾崎 公洋2004 年 51 巻 1 号 p. 19-26
発行日: 2004/01/15
公開日: 2009/05/22
ジャーナル フリーPulsed current sintering (PCS) is a process to sinter powders by applying directly a pulsed current to. The process prepares densely a sintered body at a low temperature by heating with pressing in a vacuum. In particular, this is effective to sinter metal powders with a surface oxide film, which makes those difficult to do.
To produce amorphous sintered bodies from amorphous powders requires sintering the powders at a temperature lower than the crystallization temperature of those. It is difficult that sintering of amorphous powders synthesized by mechanically alloying (MA), because the glass transformation temperature of the amorphous powder is not observed usually. By pulsed-current-sintering under a coaxial pressure more than 400 MPa, an amorphous magnesium bulk was produced from amorphous powder prepared by MA. The amorphous magnesium alloy had a high compressive strength and a high corrosion resistance. This process is applicable to an amorphous titanium powder prepared by MA.
A ferritic stainless steel consisting of iron and chromium has generally σ phase, which is hard and brittle, and it is difficult to produce a high chromium alloy. A formed body with no σ phase can be produced by pulsed-current-sintering Fe-48at%Cr mechanically alloyed powder. The sintered body showed higher than 1GPa of tensile strength and 10% of elongation. Then to use an assembling carbon die set can form a complicated near-net-shape.
A dense cermet with a fine TiC particle is hard to be made on account of the bad wettability of melted Ni to the TiC particle. To heat at a high rate by pulsed-current-sintering Ti-C-Ni mechanically alloyed powder synthesizes TiC particle in-situ while heating and produces a dense cermet. The cermet had a complicated material with fine TiC particle smaller than 1μm.
The PCS makes possible producing alloys that are hard to sinter by combining with mechanical alloying, which is a method of synthesizing powders.抄録全体を表示PDF形式でダウンロード (10465K) -
大塚 淳, 武川 淳二郎2004 年 51 巻 1 号 p. 27-30
発行日: 2004/01/15
公開日: 2009/05/22
ジャーナル フリーWe have already reported that the addition of boron powder, known as the most useful sintering enhancer for ferrous powders, was effective for the sintering of the high speed steel powder (SKH51), while a considerable grain growth, harmful to the mechanical properties of the compacts, occurred during sintering. In order to obtain the sintered compacts with high densities and fine-grained structure, 0.2-0.7 mass% Al2O3 fine powders were mixed with SKH51 steel powder together with 0.4 mass% B powder. These mixed powders were compacted and sintered in H2 atmosphere at 1453K-1493K for 2h. It was shown that the SKH51 steel powder compacts with Al2O3 and B powders were appreciably densified during sintering, compared with the compacts containing B powder alone, whereas no significant grain refinements were shown, contrary to our expection. It was considered Al2O3 fine powder prevented the formation of isolated large pores which tended to emerge during sintering of SKH51 steel powder compacts containing B alone, and resulted in the high densification. It was also shown that the hardness of the compacts after heat treatment was somewhat improved by the addition of Al2O3 fine powder together with B powder.抄録全体を表示PDF形式でダウンロード (3359K) -
針幸 達也, 伊藤 芳典, 佐藤 憲治, 三浦 秀士2004 年 51 巻 1 号 p. 31-36
発行日: 2004/01/15
公開日: 2009/05/22
ジャーナル フリーGenerally, metal injection molding (MIM) process has been utilized for mass production of complicated and near net shape parts using single material. If plural materials are joined in MIM process, multi-functional compacts can be manufactured in high productivity and high quality. Joining of stainless steels (SUS316L/SUS430L) by using insert injection molding was reported in our previous paper.
In this study, several hard materials were selected to join with stainless steels (SUS316L) by using insert injection molding. Especially, the combination of SUS316L and SUS420J2 showed good joining because of the diffusion of Ni and Mo from SUS316L to SUS420J2.抄録全体を表示PDF形式でダウンロード (2066K) -
粉体のミリ波吸収測定方法の検討佐野 三郎, 都築 明博, 李 京龍, 後藤 昭博2004 年 51 巻 1 号 p. 37-42
発行日: 2004/01/15
公開日: 2009/05/22
ジャーナル フリーMillimeter-wave absorbability of β-silicon carbide powder was measured by free-space time-domain method at the V-and W-bands millimeter-wave regions. A sample holder consisted by two Teflon disks and an acryl sleeve was used to fix the powder sample. The affection of sample holder insertion on the free-space measurement was estimated within 0.3 dB by S-parameter measurements. Noises in S parameter profiles could be excluded by applying a time-gate at the peak around 0 ns. Dielectric constants of β-silicon carbide at microwave region were measured by the coaxial probe method as a reference. Dielectric constants of β-silicon carbide showed frequency distribution at microwave region, but the change of loss tangent (tanδ) at millimeter-wave region was small. The loss tangent curve was almost flat and the value was between 0.09 and 0.13 at millimeter-wave region.抄録全体を表示PDF形式でダウンロード (2058K) -
京極 秀樹, 門村 剛志, 寺山 朗, 小松 眞一郎2004 年 51 巻 1 号 p. 43-47
発行日: 2004/01/15
公開日: 2009/05/22
ジャーナル フリーThe Ti-Ni-Cu shape memory alloy by elemental powders was fabricated by using a pulse-current pressure sintering. The influence of Cu content in Ti-Ni-Cu alloys on the microstructures, tensile and thermo-mechanical properties of the sintered compacts was investigated experimentally. The tensile properties of the as-sintered compacts could be fairly improved by performing a solution heat treatment, and the tensile strength and elongation of Ti-40.8at%Ni-9.4at% Cu alloy were approximately 500MPa and 7%, respectively. The deformation resistance of solution heat-treated compact decreased with increasing Cu content, and the yield stress of Ti-36.1at%Ni-14.1at% Cu alloy was 50MPa. The Ti-40.8at%Ni-9.4at%Cu and Ti-36.1at%Ni-14.1at%Cu alloys showed a superelastic-like behavior at a temperature above 333K. The recovery stress of solution heat-treated compact increased with increasing Cu content. The recovery stress of Ti-40.8at%Ni-9.4at%Cu alloy after loading of 2% pre-strain at the temperature change from 293K to 353K was around 350MPa.抄録全体を表示PDF形式でダウンロード (2104K) -
吉岡 尚志, 巻野 勇喜雄, 三宅 正司2004 年 51 巻 1 号 p. 48-53
発行日: 2004/01/15
公開日: 2009/05/22
ジャーナル フリーMillimeter-wave sintering of aluminum nitride for various contents of Yb2O3 sintering aid was performed under nitrogen atmosphere. Densification temperature to obtain more than 95%T.D. nonlinearly depended on the Yb2O3 content and it was found that the lowest temperature for a densification over 96%T.D. was 1600°C in the 5 wt% Yb2O3-added A1N. Dependence of densification temperature on the Yb2O3 content was closely related with liquidus temperature in the binary Yb2O3-Al2O3 phase diagram. The low densification temperature was attributed to the eutectic temperature between Yb2O3 and Yb3Al5O12. Thermal conductivity of sintered A1N increased drastically with the content of Yb2O3 up to 3 wt%. No remarkable improvement in the thermal conductivity in the range over 3 wt% Yb2O3 was caused by excess amount of Yb2O3 in the sintered AIN.抄録全体を表示PDF形式でダウンロード (1687K)
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