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Kinematical Study on the Densification Process During Pressure Sintering of Alloy Powder Utilizin Superplasticity.

利用超塑性的合金粉末加压烧结致密化过程的运动学研究。

基本信息

批准号：
63460198
负责人：
TOKIZANE Masaharu
金额：
$ 3.14万
依托单位：
Ritsumeikan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1990
项目状态：
已结题

项目摘要

An application of superplastic behavior for the pressure sintering of the alloy powder was investigated in the present study.As a fundamental study, the effects of the microstructure of the powder on the densification behavior during vacuum hot pressing (VHP) of Zn-22%Al alloy powder at 523 K was clarified based on the theoretical equation and densification mechanism map. Namely, the powder consists of fin microduprex structure was dencified by superplastic deformation in the limited range of relative density and applied pressure, while the powder consists of lamellar structure was densified according to the power low creep behavior.As the first application of the fundamental knowledge mentioned above, the effects of thermomechanical treatment which performed by combination of priorball milling and vacuum hot pressing on the densification process of SCr420 steel powder produced by plasma rotating electrode process (PREP) was examined. The results showed that the densification of the thermomechanically treated powder progressed by superplastic deformation of the powder during VHP, and the compact was composed of fine grained ferrite and spheroidized cementite particles.As the second application in the present study, we performed the examination of the densification of TiNi shape memory alloy powder produced by PREP. In this case, the densification process at temperatures from 973 to 1173 K was accelerated by prior ball milling of the powder due to considerable grain refinement. Such a grain refinement became the noticeable increase in the shape recovery strength.

研究了Zn-22%Al合金粉末超塑性行为在压力烧结中的应用，作为基础性研究，基于理论方程和致密化机理图，阐明了Zn-22%Al合金粉末在523 K真空热压过程中粉末微观结构对致密化行为的影响。即，在相对密度和施加压力的有限范围内通过超塑性变形致密化由鳍状微双相组织组成的粉末，而根据功率低蠕变行为致密化由层状组织组成的粉末。研究了预球磨和真空热压相结合的形变热处理对SCR 420钢粉末致密化过程的影响研究了等离子旋转电极工艺（PREP）制备的纳米晶薄膜。结果表明，形变热处理后的粉末在VHP过程中通过超塑性变形实现致密化，压坯由细晶铁素体和球化铁素体颗粒组成。作为本研究的第二个应用，我们对PREP法制备的TiNi形状记忆合金粉末进行了致密化研究。在973 - 1173 K温度下的致密化过程由于相当大的晶粒细化而通过粉末的预先球磨加速。这样的晶粒细化成为形状恢复强度的显著增加。