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High-Temperature Deformation and Diffusional Relaxation of Particle-Dispersion Hardened Alloys

颗粒弥散硬化合金的高温变形和扩散弛豫

基本信息

批准号：
07455278
负责人：
KATO Masaharu
金额：
$ 4.8万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455278/
关键词：
Dispersion-hardened alloys High-temperature deformation Diffusional relaxation Orowan mechanism Creep Elasticity

项目摘要

The main purpose of this research is to understand the role of diffusional relaxation on high-temperature deformation of dispersion-hardened alloys. High-temperature tensile tests were conducted using Cu-SiO_2, Cu-GeO_2 and Cu-Fe alloy single crystals and bicrystals and various stress-strain curves were obtained. In addition, intergranular brittle fracture was found to be very sensitive to the nature of grain boundaries. To quantitatively discuss these experimental results, it was necessary to obtain information on the shape change of dispersed particles that occurs during the deformation. Misorientation-dependent grain-boundary energy must also be characterized. Therefore, basic data on these quantities were also obtained.As theoretical studies, diffusional relaxation around dispersed particles was analyzed by combining mechanics, thermodynamics and kinetics and the rate equations for the relaxation process could be obtained sucessfully. Furthermore, stable shape of dispersed particles and precipitates under a given set of conditions was quantitatively analyzed using micromechanics.In comparison with the high-temperature deformation tests, low-cycle fatigue of Cu-Fe alloy single crystals were performed to reveal the effect of dispersed particles on the development of stable dislocation structure. The similarities and differences in the dislocation structure between high-temperature deformation and cyclic deformation were found very clearly.It is true that this research project has been successfully completed in a sense that it has greatly improved our understanding. What is more important, however, is that this project resulted in the discovery of various new research areas that are essential to understand the high-temperature deformation of dispersion-hardened alloys.

本研究的主要目的是了解扩散松弛对弥散硬化合金高温变形的作用。对Cu-SiO_2、Cu-GeO_2和Cu-Fe合金单晶和双晶进行了高温拉伸试验，得到了各种应力-应变曲线。此外，沿晶脆性断裂被发现是非常敏感的晶界的性质。为了定量地讨论这些实验结果，有必要获得关于在变形期间发生的分散颗粒的形状变化的信息。还必须表征取向差相关的晶界能。作为理论研究，结合力学、热力学和动力学分析了弥散颗粒周围的扩散弛豫过程，得到了弛豫过程的速率方程。此外，还利用细观力学定量分析了弥散相和析出相在一定条件下的稳定形态，并通过Cu-Fe合金单晶的低周疲劳试验与高温变形试验对比，揭示了弥散相对稳定位错结构发展的影响。发现了高温变形和循环变形位错结构的异同，从某种意义上说，这个研究项目的成功完成，极大地提高了我们的认识。然而，更重要的是，该项目发现了各种新的研究领域，这些领域对于理解弥散硬化合金的高温变形至关重要。