摘要本试验通过真空扩散渗铝锌的方法对 AZ91D 镁合金进行表面合金化处理，主要 研究内容如下：本次试验通过真空钼丝炉来实现真空扩散渗铝锌，研究了保温时间、温度以及渗 剂中铝锌质量比等不同工艺参数对渗层的的影响，通过蔡司金相显微镜、扫描电镜观 测不同工艺参数下的渗铝锌层组织结构，采用电化学工作站、显微硬度计对不同工艺 参数下试样的耐蚀性、硬度进行分析，最后采用 EDS 能谱分析仪和 X 射线衍射仪对 最佳工艺参数下的 AZ91D 镁合金试样渗铝锌层进行成分分析和物相分析；79382

研究发现，扩散渗温度在 320-350℃范围内，渗层厚度随着温度的上升而增加； 保温时间在 90-110min 范围内，渗层厚度随着保湿时间的上升而增加；铝锌质量比越 接近，渗层厚度越大。试验结果表明在 330℃下用铝锌质量比为 2:3 的渗剂保温 100min 可以获得性能较为理想的渗层，为改善 AZ91D 镁合金表面合金化性能提供了参考依 据。

本次试验数据说明，真空扩散渗铝锌这种方式可以有效实现 AZ91D 镁合金表面 合金化，增强了 AZ91D 镁合金的耐蚀性，提高了硬度。

毕业论文关键词：镁合金；渗铝锌；耐腐蚀性

Abstract In this test，the surface alloying treatment of AZ91D magnesium alloy is carried out by the method of Al-Zn co-diffusion obtained by vacuum diffusion。The main research contents are as follows：

The vacuum molybdenum wire furnace is used to realize the Al-Zn co-diffusion obtained by vacuum diffusion。The influence of different process parameters such as the time ， temperature and  the  quality  ratio of  aluminum  and  zinc  on the  coating layer is

studied。The microstructure of Al-Zn layer in different process parameters is observed by means  of  metallographic  microscope  and  scanning  electron  microscope。The  corrosion

resistance and hardness of the samples are analyzed by electrochemical workstation and micro hardness tester under different technological parameters。In the end，I use the   EDS

energy spectrum analyzer and X-ray diffraction to analyse the Al-Zn coating of composition and phase of AZ91D magnesium alloy sample under the optimum technological parameters。

Study finds that the thickness of the layer increases with the increase of temperature when the diffusion temperature in 320-350℃ range or holding time in 90-110min range。When the quality of aluminum zinc ratio is near，the thickness of the layer will be grater。The experimental results show that the ideal Al-Zn layer can be obtained by using

Al-Zn mass ratio of permeability agent 2:3 with heat insulation at 330℃ for 100min。It provides a reference for improving the surface alloying of AZ91D magnesium alloys。

The test data shows that the surface alloying treatment of AZ91D magnesium  alloy can be effectively carried out by the method of Al-Zn co-diffusion obtained by vacuum diffusion。This method can enhance the corrosion resistance of AZ91D magnesium alloy and improve the hardness。

Keywords: magnesium  alloy；Al-Zn  co-diffusion；corrosion resistance

目录

第一章 绪论 1

1。1 镁及镁合金的简介 1

1。1。1 镁的发现 1

1。1。2 镁的性质和加工性能 1

1。1。3 镁的应用 2

1。1。4 镁合金的性能优缺点 2

1。1。5 镁合金的应用 3

1。2 国内外研究现状及存在的问题