黄河科技学院材料成型毕业论文 - 图文

单位代码 02 学 号 080118017 分 类 号 TH6 密 级

毕业论文

镁合金表面扩渗Al-Zn工艺及对其性能的影响

研究

院（系）名称 专 业 名 称 学 生 姓 名 指 导 教 师

工学院

材料成型及控制工程

陈三雨 张保丰

2012年 5 月 15 日

黄河科技学院毕业论文 第I页

镁合金表面扩渗Al-Zn工艺及对其性能的影响研究

摘 要

镁及镁合金具有一系列的性能优点，其密度小，比刚度高，电磁屏蔽性能优异，热成型和切削加工性好，同时还具有易于回收再利用等突出优点，被誉为2l世纪的绿色金属材料。AZ91D镁合金是工业应用最为广泛的镁合金之一。

但镁是活泼金属，且镁的氧化膜疏松多孔，故镁及镁合金的耐腐蚀性很差，影响了其应用性。目前主要采取以下几种方法来解决镁合金耐腐性问题， 一是提高镁合金纯度或研制新合金，二是采用快速凝固工艺，三就是采用表面处理技术，生成涂层或膜以及进行表面改性。

本文主要是通过热扩渗Al、Zn，来改善镁合金的性能。采用切割机切取镁合金块，然后将其打磨、抛光，制成一定尺寸的试样，清洗试样烘干备用，再配置一定量的纯A1渗剂、50%Al+50%Zn渗剂作为扩渗介质。在温度可控的箱式电阻炉内，在不同温度下， 对AZ91D镁合金进行不同时间的表面扩渗处理。然后观察试样的金相组织与渗层厚度，分析Al、Zn对AZ91D镁合金表面组织的影响，通过硬度测试对比分析不同条件下进行表面扩渗对镁合金的硬度方面带来的变化与影响，在利用腐蚀试验对基体和渗层的耐蚀性进行了对比分析。试验表明：观察试样的显微组织发现，扩渗过Al、Zn的试样表面显微组织发生明显变化，通过硬度测试与浸液腐蚀和电极腐蚀证明扩渗层的形成能够提高镁合金的表面硬度与耐腐蚀性。

关键字：AZ91D镁合金，扩渗，硬度，耐腐蚀性

黄河科技学院毕业论文 第II页

Effect Of Solid Diffusion of Al-Zn on the Properties of AZ91D

Magnesium Alloy

Author: Chen Sanyu

Tutor : Zhang Baofeng

Abstract

Magnesium and magnesium alloys with a range of performance benefits， their low density and specific rigidity， electromagnetic shielding performance， thermoforming and good machinability， and also highlight the advantages of easy recycling use， known as the green metallic materials of the 21st century． AZ91D magnesium alloy is one of the industry's most widely used magnesium alloy．

Magnesium is the active metals， and oxide membrane of magnesium is porous， so the poor corrosion resistance of magnesium and magnesium alloys， Affect its application． Mainly take the following are several ways to solve the corrosion resistance of magnesium alloy， the first is to enhance the purity of magnesium alloy， or the development of new alloys， the second is using the rapid solidification process， three is the use of surface treatment technology to generate a coating or membrane， and surface modification sex．

This paper is to discuss the diffusion of Al through the hot， of Zn， to improve the performance of magnesium alloy． The cutting machine cut magnesium alloy block and then polished， polished， made of a certain size of the sample， cleaning sample and then drying， and then configure a certain amount of pure Al penetration， 50% Al +50% Zn penetration as a diffusion dielectric． In a temperature-controlled box-type resistance furnace AZ91D magnesium alloy get the surface diffusion at different temperatures and different times． And then observe the microstructure and diffusion layer thickness of the sample the

黄河科技学院毕业论文 第III页

thickness of the nitrided layer， analysis the impact of Al 、Zn in the surface structure of AZ91D magnesium alloy， hardness test comparison analysis the impact of surface diffusion on the hardness of the magnesium alloy under different conditions． In the use of corrosion test analysis of the corrosion resistance of the original sample and the diffusion． The tests showed: Microstructure observation of the specimen found that diffusion of Al， Zn specimen surface microstructure change significantly， by means of hardness testing and immersion corrosion and electrode corrosion proof of the existence of the diffusion layer can significantly increase the magnesium alloy surface hardness and corrosion resistance．

Key words: AZ91D Magnesium Alloy， Diffusion， Hardness， Corrosion Resistance

黄河科技学院毕业论文 第IV页

目 录

1 绪 论 ····························································································································· 1

1.1 镁及镁合金的历史 ································································································ 1 1.2 国内镁及镁合金的现状 ························································································ 2 1.3 镁及镁合金的缺点 ································································································ 3 1.4 镁合金表面改性方法 ···························································································· 4

1.4.1 表面扩渗合金化改性技术 ······················································ …… 此处隐藏：1779字，全部文档内容请下载后查看。喜欢就下载吧 ……