半固态材料触变成形通用本构方程及其优化  

MODELING AND OPTIMIZATION OF GENERAL CONSTITUTIVE EQUATION OF SEMI-SOLID THIXOFORMING

作　　者：余小鲁[1] 李付国[1] 李淼泉[1] 

机构地区：[1]西北工业大学材料科学与工程学院,西安710072

出　　处：《机械工程学报》2007年第10期72-76,共5页Journal of Mechanical Engineering

基　　金：航空基础科学基金(03H53048);'十五'航空预研资助项目

摘　　要：采用半固态成形机理分析和试验研究相结合的方法,建立半固态触变成形的粘塑性本构方程,并提出本构方程的优化新方法。通过半固态Al-4Cu-Mg合金的等温压缩试验研究,分析试验数据,得到本构方程中的4个待定系数,并以此作为优化设计的初试值。结合本构方程的形式,对其进行特性分析和优化。将含优化变量的本构方程作为子程序引入到有限元数值模拟中,可以得到对照热模拟试验结果的若干工艺条件下半固态Al-4Cu-Mg合金的应力应变曲线。通过比较有限元数值模拟结果和热模拟试验结果可知,利用提出的本构方程优化新方法,不仅可以剔除热模拟试验数据中几何效应的影响,而且还能准确地描述半固态材料的触变成形规律,从而可以提高数值模拟的精度与可靠性。The constitutive equation of semi-solid thixoforming is modeled on the basis of combining analysis of deformation mechanism with experimental investigation. The undetermined coefficients in constitutive equation can be achieved by analyzing experimental data and act as the initial value of optimization design. An optimization method for this constitutive equation is discussed. The constitutive equation with optimized coefficients is imported to numerical simulation of isothermal compression of semi-solid Al-4Cu-Mg alloy as a subroutine, thereby obtaining the numerical data of flow stress under several processing conditions. By the aid of this method, geometric effect of deformation can be removed and nature of semi-solid thixoforming described accurately. As a result, the new optimization method of constitutive equation can improve the validity of numerical simulation significantly, which is presented by means of comparing the results of the numerical data with experimental data.

关 键 词：半固态 触变成形 本构方程 优化 

分 类 号：TG146.2[一般工业技术—材料科学与工程]