基于ALE方法大挤压比Al-Cu-Mg合金等温挤压研究

Study on Isothermal Extrusion of Al-Cu-Mg Aluminum Alloy with Large Extrusion Ratio Based on ALE Method

为了获得大挤压比Al-Cu-Mg合金高精度等温挤压件,有必要精确控制其均匀的挤压出口温度和变形组织。为此,基于任意拉格朗日-欧拉(ALE)方法,采用ABAQUS有限元软件对其等温挤压过程进行模拟。通过热压缩试验获得了Al-Cu-Mg合金在不同温度和应变速率下的真应力-真应变本构关系,建立了一个新的等温挤压过程多场耦合计算模型。通过该模型,研究了挤压速度、坯料温度、模具温度对出口温度的影响规律以及挤压产品温度场、应变速率场的分布特点;并通过开展Al-Cu-Mg合金铸棒等温挤压工艺实验验证了所模拟等温挤压工艺参数的准确性,并对变形材料进行了EBSD分析和力学性能测试。结果表明:0.5 mm/s挤压速度可保持模孔温度基本恒定,其中坯料温度450℃,挤压筒430℃,以及模具温度为400℃,挤压后试样的晶粒明显细化,择优排列形成平行于挤压方向的<111>丝织构,表现出优异的拉伸性能。

In order to obtain high precision Al-Cu-Mg aluminium alloy isothermal extrusion parts with large extrusion ratio,it is necessary to accurately control the uniform exit temperature and deformation microstructure.Therefore,based on arbitrary Lagrange Eulerian(ALE)method,the isothermal extrusion process was simulated by ABAQUS finite element software.True stress-true strain curves of Al-Cu-Mg alloy at different temperatures and strain rates were investigated by hot compression test.A new multi-physics coupling numerical model for isothermal extrusion process was established.The influence of extrusion speed,billet temperature and die temperature on the exit temperature and the distribution characteristics of the temperature field and strain rate field of extrusion products were studied.The isothermal extrusion was conducted to verify the model through the EBSD analysis and mechanical properties test of the deformed material.The results show that extrusion speed of 0.5 mm/s can keep the exit temperature basically constant,in which the billet temperature is 450℃,cylinder temperature is 430℃,and die temperature is 400℃.After extrusion,the grains of the sample are significantly refined,and the preferred arrangement is to form<111>silk texture parallel to the extrusion direction,showing excellent tensile properties.