高熵合金的塑性变形机理研究

摘要高熵合金是一种含有多种主元素的新型金属材料。具备特殊的物理、力学性质和广阔的应用前景。但高熵合金相对复杂的体系和结构对其塑性变形的研究造成了一定的障碍。Al-Co-Cr-Cu-Fe-Ni 系高熵合金是研究比较多的高熵合金体系之一，其中，Al0.3Cu0.5CoCrFeNi 高熵合金在合适的热处理条件下具备单一 FCC 结构，具有良好的塑性和强度。因此，它是用来研究高熵合金的塑性变形机理的理想模型材料。 21757
在本毕业设计中，作者用定量 X 射线衍射峰形分析和透射电子显微镜等表征手段对淬火态的 Al0.3Cu0.5CoCrFeNi 高熵合金在经历塑性变形后其内部的晶体结构，缺陷种类及其组态，亚晶尺寸和位错密度进行分析。结果表明，在室温轧制后， Al0.3Cu0.5CoCrFeNi 高熵合金内部的缺陷以全位错为主，但也存在少量的全位错分解以及层错。X 射线衍射线形分析表明，随着轧下量的增加，亚晶尺寸减小，位错密度增大。
关键词高熵合金塑性变形 XRD 线形分析单线法缺陷
Title Plastic deformation mechanism research of a kind of high-entropy alloy
Abstract
High-entropy alloy (HEA) is a new class of metallic materials with multiple
principal elements. It processes special physical and mechanical
properties, as well as wide application prospect. But the wide range of
available composition and relatively complex microstructure hinders
research on deformation mechanisms of HEAs. Al-Co-Cr-Cu-Fe-Ni system HEA
is one of the best studied HEAs. Among them, Al0.3Cu0.5CoCrFeNi HEA consists
of simple FCC structure under specific heat-treatment condition. It
exhibits good plasticity and moderate strength. Thus, it’s an ideal model
material for plastic deformation mechanism research.
In this graduation dissertation, by taking advantage of X-ray diffraction
(XRD), transmission electron microscopy and other characterization
methods, the author investigated the crystal structure, types of defects
and their configuration, the crystallite size and the dislocation density
of the water-quenched Al0.3Cu0.5CoCrFeNi HEA after plastic deformation. The
results indicated that after cold rolled at room temperature, the defects
in the Al0.3Cu0.5CoCrFeNi HEA were mainly full dislocations, but there were
also certain extent of full dislocation dissociation and stacking
faults.XRD line profile analysis showed quantitatively that the
crystalline size decreased and the dislocation density increased with the
increase of reduction.
Keywords   high-entropy alloy    plastic deformation    XRD line profile
analysis    single-line method    defects
目   次

1 引言 1
1.1 研究背景及意义 1
1.2 Al0.3Cu0.5CoCrFeNi 高熵合金的显微结构2
1.3 XRD 与 TEM 在研究材料塑性变形中的应用2
1.3.1 高熵合金衍射线宽化效应…4
1.3.2 X 射线衍射峰的定量描述…4
1.3.3 线对法计算形变层错几率…5
1.3.4 单线法计算亚晶尺寸和位错密度6
2 实验步骤9
3 结果与讨论…10
3.1 塑性变形在高熵合金中引入的缺陷类型10
3.2 使用Jade软件对X射线衍射峰形进行拟合…11
3.3 塑性变形后高熵合金的形变层错几率…12
3.4 塑性变形后合金中的亚晶尺寸和缺陷密度…13
结论   18
致谢   19
参考文献20
引言
1．1 研究背景及意义
随着传统合金的研究和应用以及趋于饱和，人们开始研发新型合金。人们有理由高熵合金的塑性变形机理研究:http://www.751com.cn/cailiao/lunwen_14105.html