镁合金阶梯变速等温锻造成形的组织演化规律与调控机理

项目名称： 镁合金阶梯变速等温锻造成形的组织演化规律与调控机理

项目编号： No.51505504

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 机械、仪表工业

项目作者： 黄始全

作者单位： 中南大学

项目金额： 20万元

中文摘要： 阶梯变速等温锻造是实现复杂镁合金构件高效超塑性成形的有效途径。在阶梯变速锻造过程中，组织预测与调控是使锻件晶粒细化实现超塑性压缩的重要手段。然而，阶梯变速锻造极宽的速度范围导致多种组织演化机制并存，且受阶梯变速的强激励作用组织演化机制与规律变得极为复杂。因此，阶梯变速锻造的组织演化规律与调控机理是亟待解决的难题。.本项目拟通过恒速率与阶梯变速压缩实验，揭示阶梯变速压缩组织演化机制与规律，建立考虑阶梯变速条件、变形存储能与初始组织状态的组织演化模型；探明压缩超塑性的变形与组织条件，在此基础上，建立阶梯变速锻造有限元分析模型，并通过阶梯变速等温锻造工艺实验进行验证与改进；研究温度与阶梯变速路径对组织状态的影响规律与作用机理，探明阶梯变速锻造的组织调控机理，通过变形过程的晶粒细化实现构件一次超塑性成形。本项目的研究成果可为复杂镁合金构件高效超塑性成形提供理论指导。

中文关键词： 阶梯变速锻造；镁合金；组织演变；等温锻造；超塑性

英文摘要： Stepped-speed isothermal forging is an effective way to produce complex magnesium components with high efficiency by superplastic deformation. During this process, microstructure prediction and control is the important measure to refine grain, through which superplastic deformation can be achieved. However, various microstructure evolution mechanism is exists for huge range of speed during stepped-speed forging. Moreover, its behavior becomes more complex for stepped-speed, which changes microstructure evolution rule and mechanism of magnesium alloy. So, research work, such as microstructure evolution rule and control methodology, is in urgent need to be studied..The project is to reveal microstructure evolution rule and mechanism during stepped-speed forging. Compression tests with constant-speed and stepped-speed will be carried out for this goal. And, microstructure evolution models are going to be established by combining influences of deformation conditions, storage energy and initial microstructure. On the other hand, based on microstructure status and its deformation condition of superplastic compression, finite element analysis models for stepped-speed forging will be developed. And, for verification and improving of these models, stepped-speed isothermal forging tests are going to be carried out on isothermal die forging press. Then, influences of temperature and stepped-speed on deformation state and microstructure will be studied. Consequently, microstructure control mechanism can be revealed. Through this way, grain will be refined and superplastic forging is gonging to be achieved. So, magnesium components can be precisely produced during one-step forming. The research findings of this project can provide a theoretical guidance to manufacture complex magnesium components through superplastic compression with high efficiency.

英文关键词： stepped-speed forging;magnesium alloy;microstructure evolution;isothermal forging; superplasticity