摘要采用等径角挤压(ECAP)塑性变形法制备了8道次的纯钽试样,得到了超细晶钽。利用超细晶钽在473 K-77 K做应变速率突变拉伸拉伸实验,测得各温度下的应变速率敏感性指数m,m值随着温度的升高而增大。通过观察超细晶钽在不同温度退火下的微观组织和硬度的变化,研究了钽的再结晶行为。样品在900 K左右开始发生再结晶行为,约1200 K再结晶行为基本结束。
借助热激活机制,在不同温度水平下,研究了超细晶钽的宏观力学性能与微观特征的关系,并从超细晶到粗晶范围内研究其晶粒尺寸效应。87681
毕业论文关键词 超细晶钽 等径角挤压变形 应变速率敏感性指数 再结晶
毕业设计说明书外文摘要
Title Thermal stability and mechanical properties of ultrafine grained tantalum at high and low temperature
Abstract In this paper, 8 pure tantalum samples were prepared by equal channel angular pressing (ECAP)。Strain rate jump test has been carried out over a range of temperatures (77 K- 473 K) on the ultrafine grained tantalum,and the strain-rate sensitivity index m was measured at different temperatures, and the m value increased with increase in the deformation temperature。 The recrystallization behavior was observed by the change of microstructure and hardness at different annealing temperature。The material began to occur recrystallization behavior about 900 K,and about 1200 K recrystallization behavior basically ended。
In this paper, the relationship between the macro mechanical properties and the microscopic characteristics of ultrafine grained tantalum at different temperature was studied by means of the thermal activation mechanism。
Keywords UFG tantalum ECAP Strain-rate sensitivity Recrystallization
目 次
1 绪论 1
1。1 引言 1
1。2 剧烈塑形变形法 1
1。2。1 等径角挤压变形(ECAP) 1
1。2。2 高压扭转变形(HPT) 3
1。2。3 复合轧制(ARB) 4源-于,优+尔^论=文.网wwW.yOueRw.com 原文+QQ752.018766
1。3 材料力学行为及其热力学参数 4
1。3。1 应变速率敏感系数(SRS) 4
1。3。2 激活体积 6
1。3。3 应变速率敏感系数和激活体积的关系 6
1。3。4 纳米压痕技术(Nanoindentation) 7
1。4 电子背散射衍射(EBSD)简介 8
1。5 差示扫描量热法(DSC) 9
1。6 本章小结 9
2 实验过程 10
2。1 等径角挤压变形 10
2。2 退火 10
2。3 电子背散射衍射(EBSD) 10
2。4 应变速率突变拉伸实验 10
2。5 纳米压痕 10
2。6 差示扫描量热法(DSC) 超细晶钽高低温力学性能及热稳定性研究:http://www.youerw.com/cailiao/lunwen_142823.html