文档介绍：摘要
由于AZ31镁合金是密排六方晶体结构,滑移系少,室温下塑性较差,目前人们主要通过细化晶粒来提高其强度和塑性。开发新的高性能镁合金系列是目前研究的主要趋势,但对现有镁合金系统进行适当的工艺处理也可能成为改善材料性能的廉价而有效的方式。
由于低温塑性变形过程中容易导致裂纹的产生,加之镁合金塑性较差,因此有关镁合金在低温情况下变形的研究很少。为此,本文研究了室温下AZ31镁合金线材的拉拔工艺,并获得了超过60%的最大累积冷变形程度。之后对不同冷变形程度的线材进行了不同工艺的再结晶退火处理。采用金相显微镜(OM)对各种退火线材进行了微观组织观察截线法测定了其晶粒尺寸,获得了退火工艺与再结晶晶粒尺寸的关系。采用Instron5567对不同工艺下的线材进行了室温拉伸试验,测定了其力学性能。
关键词: 镁合金,冷拉拔,再结晶退火,显微组织,力学性能
Abstract
Because of the hexagonal closed packed (HCP) crystal structure and lack of enough slip systems, AZ31 magnesium alloy possesses poor formability at room temperature. Grain refinement is known to be an effective method to improve the poor mechanical properties in recent years. Now, the important fields about magnesium alloy are to explore some new magnesium with high properties. But appropriate processing treatment with magnesium is probably to be an effective and low-cost method of improving their properties.
Crack can easily appears at low temperatures, which leads to poor properties of magnesium, thus research on magnesium at low temperatures is very few. In this paper, study on cold drawing at room temperature and annealing process at various temperatures of AZ31 magnesium alloy were carried out. Effects of annealing process on grain refinement of AZ31 magnesium alloy were analyzed in this paper. Tension test was applied on various-processed AZ31 Mg alloy wires using Instron5567 tension machine.
Keywords:AZ31 magnesium alloys, cold drawing, annealing, microstructure, mechanical properties.
目录
摘要 I
Abstract II
第1章绪论 5
设计的目的及意义 5
论文综述 5
引言 5
稀土的特性 6
稀土在变形镁合金中的应用 7
塑性变形强化镁合金(挤压) 7
实验内容、技术要求(研究方法) 9
设计进度安排 9
本章总结 10
第2章实验材料及试验方法 11
实验材料 11
试验及检测设备 11
热处理实验 11
力学拉伸实验 11
实验及检测设备 12
金相观察 12
本章总结 12
第3章挤压态MB26镁合金热处理组织及性能研究 13
热处理实验方案制定 13
不同热处理试样常温力学性能实验 14
不同热处理条件下MB26镁合金组织分析 15
铸态组织与原始挤压态组织对比 15
固溶处理后组织及性能分析 16
固溶+时效处理后组织及性能分析 18
时效处理后组织及性能分