摘要：镁合金是密排六方结构，在室温下只有基面滑移可以启动。因此，塑性改善对于镁合金的更广泛的应用是非常重要的。轧制技术因为其效率较高，被认为是一种较有效的加工方式。本实验通过对AZ31镁合金变面轧制处理，观察轧制后的组织结构，并通过拉伸试验测得力学性能，观察断口形貌。变面轧制过程中发现拉伸孪晶、压缩孪晶、双孪晶三类的孪晶，其中双孪生是形成双峰织构的机制。变面轧制期间观察到动态再结晶，动态再结晶的成核过程是依赖于亚晶粒的合并。轧制过程中出现的织构有两类：奇道次的基面织构，偶道次的双峰织构。晶粒细化、孪晶界、织构硬化及高位错密度等原因引起织构强化，运用霍尔佩奇关系可以解释偶道次的织构强化。

关键词 镁合金 轧制 孪晶 织构 晶粒细化

毕业设计说明书外文摘要

Title Mechanical properties and microstructural evolution   of variable-plane rolled AZ31 magnesium alloy

Abstract：The magnesium alloy is HCP crystal structure, and only the base slip system can be activated at room temperature. Therefore, plastic improvement is very important for the wider application of magnesium alloys. Rolling technology is considered to be a more effective way because of its high efficiency. In this experiment, the microstructure of rolled AZ31 magnesium alloy has been observed, and the mechanical properties have been observed by tensile test, and the fracture morphology has been observed. During the process of rolling, we can find extension twins, contraction twins and double twins; the double twinning is the mechanism of the formation of double-peak texture. The nucleation process of dynamic recrystallization is observed due to subgrain consolidation during rolling. There are two kinds of textures in the rolling process: basal texture in odd-pass and double-peak basal texture in even-pass. Texture enhancement is caused by grain refinement, twin boundary, texture hardening and high dislocation density, which can be explained by Hall-Petch relation.

Keywords  magnesium alloy  rolling  twin  texture  grain refinement

目 次

1 引言 1

1.1 镁及镁合金 1

1.2 变形镁合金 3

1.3 镁合金轧制技术 4

1.4 本研究课题的创新点 8

2 实验过程 9

2.1 实验准备 9

2.2 实验操作… 10

3 实验结论… 16

3.1 光学显微结构… 16

3.2 TEM所得显微组织… 18

3.3 织构的观察… 20

3.4 力学性能测量… 21