梯度应变改善镁合金挤压板材成形性的基础研究

项目名称： 梯度应变改善镁合金挤压板材成形性的基础研究

项目编号： No.51474043

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 矿业工程

项目作者： 潘复生

作者单位： 重庆大学

项目金额： 86万元

中文摘要： 镁合金板材制备加工通常采用对称变形的热轧工艺，导致工艺流程长、加工成本高，而且具有很强的（0002）基面织构，使镁合金板材塑性成形性差，应用受到极大限制。为此，本项目提出以非对称挤压方式构建梯度应变，使镁合金板材晶粒c轴倾转，将短流程挤压与梯度应变弱化基面织构进行一体化耦合，获得成形性显著改善的低成本镁合金挤压板材。通过研究模具几何结构、挤压工艺参数和梯度应变之间的内在联系并建立物理模型，发展合理的梯度应变控制机制和镁合金板材挤压模具，研究表征梯度应变条件下镁合金挤压板材的组织与微结构演变规律以及梯度应变特征参量与组织特征参量的定量关系模型，研究表征镁合金挤压板材的晶粒取向和织构形成机制及其遗传演变，研究表征镁合金挤压板材的成形特性和各向异性特征，建立从挤压模具几何结构、梯度应变特征、组织与微结构、晶粒取向和织构弱化、到各向异性表征的高成形性镁合金挤压板材制备的理论途径和技术原型。

中文关键词： 镁合金板材；塑性变形；织构；力学性能

英文摘要： Generally, magnesium alloy plate is processed by symmetric deformation techniques and resultingly this process results in a long procedure and high cost, and also a strong (0002) basal texture is formed which largely worsens the formability of magnesium alloy plate and its wider applications are limited. Therefore, asymmetric extrusion is proposed to setup gradient strain along the thickness direction of the plate and thus c-axis of magnesium grain will be tilted at some degree through composite integration of short procedure extrusion and gradient strain to weaken the basal texture, so magnesiuam alloy plates with improved formability and low cost will be prepared. Through the raltionship between geometry of extrusion mould, extrusion parameters and gradient strain and then its physical model in order to develop reasonable gradient strain control and extrusion mould, through the research on evolution of microstructure and ultramicrostructure and the quantitative expression beteen gradient strain and microstructure, through research on crystal orientation and texture and their evolution, through the characterization of formability and anisotropical properties, theory and model about highly formable magnesium alloy extrusion plates will be established by from geometry structure of extrusion mould, gradient strain, microstructure, grain oreintation and basal texture weakening, to anisotropic properties.

英文关键词： magnesium alloy plate;plastic deformation;texture;mechanical property