超细晶镍的组织和性能研究

摘要等径角挤压(ECAP)作为剧烈塑性变形(SPD)的方法之一，可以有效细化晶粒，提高材料的力学性能。本论文在室温和280℃下分别对不同纯度的Ni(99.98%和99.5%)实施 ECAP变形，最高达到12道次，成功制备超细晶镍。利用透射电子显微镜对不同挤压道次变形后纯镍的微观组织进行了观察和表征，得到了晶粒尺寸分布及演化规律。通过显微硬度、拉伸试验对超细晶组织的力学性能进行测试，分别建立了强度、塑性指标对应变的关系曲线。最后比较了不同纯度、温度及加工道次下ECAP纯镍的微观组织和力学性能，发现杂质元素对其组织、性能演化有显著影响。
关键词等径角挤压纯镍组织力学性能杂质毕业设计说明书（论文）外文摘要10874
Title The Study of Microstructure and Mechanical Properties of Ultra-fine Grained Nickel
Abstract
Equal Channel Angular Pressing (ECAP) is one of the Severe Plastic Deformation (SPD) methods that can be used for producing ultra-fine grained materials with high mechanical properties. In this paper, nickel with different purities (99.98% and 99.5%) were processed by ECAP (up to 12 passes) at room temperature and 280℃ respectively. Transmission electron microscope (TEM) was used to observe the microstructure evolution and characterize the grain size distribution. Both microhardness and tensile test were carried out to analyze the mechanical properties of
ultra-fine grained nickel; curves of strength and ductility with respect to stain were established respectively. Finally, comparing results of microstructure and mechanical properties of nickel under different deformation temperatures and strain, it is found that impurities play a key role in microstructure evolution and mechanical properties of nickel during ECAP.
Keywords Equal Channel Angular Pressing; Nickel; Microstructure; Mechanical Properties; impurities
目   次
1 绪论   1
1.1 研究背景   1
1.2 超细晶材料的制备工艺   2
1.2.1 轧制法(Rolling)   2
1.2.2 剧烈塑性变形法(SPD)   3
1.3 ECAP制备超细晶镍的研究现状   8
1.3.1 ECAP超细晶镍的组织特征   8
1.3.2 ECAP超细晶镍的力学性能特征   10
1.4 课题研究的内容、目标及创新性   12
1.4.1 课题研究的内容   12
1.4.2 课题研究的目标   12
1.4.3 课题研究的创新性   13
2 实验材料及方法   14
2.1 实验材料   14
2.2 实验路线与方案   14
2.2.1 实验路线   14
2.2.2 实验方案   15
2.3 实验设备   15
2.4 实验方法   15
2.4.1 ECAP变形   15
2.4.2 光学金相组织观察   16
2.4.3 透射电镜组织观察   16
2.4.4 显微硬度测试   16
2.4.5 力学拉伸试验   17
3 组织观察与分析   18
3.1 光学显微组织观察   18
3.2 透射电镜显微组织观察   19
3.2.1 室温99.98%镍ECAP组织   19
3.2.2 280℃99.98%镍ECAP组织   21
3.2.3 小结   23
4 力学性能测试与结果分析   24
4.1 99.98%镍的拉伸性能分析   24
4.2 99.98%镍的显微硬度分析   25
4.3 小结   25
5 杂质元素对ECAP纯镍组织性能影响   26
5.1 室温下组织对比分析   26
5.2 280℃下组织对比分析   27 超细晶镍的组织和性能研究:http://www.youerw.com/cailiao/lunwen_10059.html