含微量Zr的Mg-Zn基合金的时效析出行为及强化机制

项目名称： 含微量Zr的Mg-Zn基合金的时效析出行为及强化机制

项目编号： No.51201088

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 金属材料学科

项目作者： 朱红梅

作者单位： 南华大学

项目金额： 25万元

中文摘要： Mg-Zn基镁合金具有固溶强化和时效强化双重效应，是目前典型的一类商用镁合金材料。然而，Mg-Zn基合金的时效析出强化相普遍存在析出密度较低、尺寸粗大且分布不均匀等缺点，大大限制了该系列合金的应用范围和发展空间。Zr是镁合金中常见的一种合金化元素，但大部分研究和应用都只集中在细化合金晶粒方面。本项目选择Mg-Zn基合金为研究对象，通过添加微量Zr和第四组元以及改变固溶处理工艺来调控合金的时效析出行为，提出一条以富Zr相为异质形核中心来提高合金时效强化相的析出密度和分布均匀性，从而提高合金时效强化效应的新思路和新途径。采用先进的材料分析技术重点研究微量Zr对Mg-Zn基合金固溶和时效析出行为的影响规律及微观机制，探明富Zr相的结构成分信息、析出特性及其组织演变过程，探索Mg-Zn基合金中主要时效强化相的有效调控手段及强化机制，为高强度轻质镁合金的开发与应用提供重要的理论指导和技术支撑。

中文关键词： Mg-Zn基合金；微合金化；热处理；时效析出；组织演变

英文摘要： Mg-Zn based magnesium alloys are typical commercial materials of solid solution strengthening and age hardening effects. However, the further application and development of such alloys has been greatly limited due to the low number density, coarse size and inhomogeneous dispersion of the age-hardening precipitates. Zr is a common alloying element for magnesium alloys, but most of studies and applications focused on its grain refinement effect. In this project, the controlling of the aging precipitation behavior of Mg-Zn based alloys by microalloying Zr, the fourth element and adjusting the solution treatment process will be studied. A unique method to enhance the number density and homogeneity of the main strengthening precipitates and thus the age-hardening effect of Mg-Zn based alloys is proposed. The effects and mechanism of the solutionization and aging precipitation behavior of Mg-Zn based alloys modified by trace Zr will be investigated by advanced material analysis techniques. The crystallography, chemical composition, precipitation characteristic and microstructure evolution of the Zr-rich phases will be explored. The effective ways to control the precipitation of the dominant age-hardening phases and the strengthening mechanism of Mg-Zn based alloys will be studied. This project aims to provide a signif

英文关键词： Mg-Zn based alloys；microalloying；heat treatment；aging precipitation behavior；microstructure evolution