基于数值模拟和实验的Mg/Al复合管材成形工艺研究

Forming Process of Mg/Al Composite Tubes Based on Numerical Simulation and Experiment

目的为了实现Mg/Al双金属管材的良好成形,提出了一种新方法,即将直接挤压和扩径剪切变形工艺相结合来制备具有良好性能的Mg/Al双金属管材,并探究挤压温度对Mg/Al复合管材成形过程的影响。方法采用DEFORM-3D有限元软件对Mg/Al双金属管材成形过程进行模拟,以定量分析不同挤压温度对生产的复合管材的影响,并结合模拟结果了解共挤过程中铝和镁合金之间发生的材料流动和冶金反应特点。对挤出管材进行微观组织和力学实验表征。结果仿真结果表明,由于材料特性的差异,挤压温度对挤压双金属结合性能的影响体现在多个方面,如挤压过程中原子扩散能、流动应力差异等。硬度测试结果表明,合理控制挤压温度可以在减小结合层厚度的同时提升基体材料的硬度。结论由直接挤压-扩径剪切变形(DEES)工艺制备的Mg/Al双金属复合管材结合良好,结合界面无缺陷和裂纹。结合层厚度在390℃时最低,在420℃时最高,当挤压温度为390℃时,基材的硬度最高,应该合理控制挤压温度以获得更优性能的复合管材。DESS工艺可以有效细化晶粒,最终形成均匀细小的等轴晶。

The work aims to propose a new method to achieve good forming of Mg/Al bimetallic tubes,which combines direct extrusion and expanding shear deformation processes to prepare Mg/Al bimetallic tubes with good performance,and to investigate the effect of extrusion temperature on the forming process of Mg/Al composite tubes.The DEFORM-3D finite element software was applied to simulate the forming process of Mg/Al bimetallic tubes to quantify the effect of different extrusion temperature on the produced composite tubes,and combine the simulation results to understand the material flow and metallurgical reactions between aluminum and magnesium alloys during co-extrusion.The microstructure and mechanical experimental characterization of the extruded tube were carried out.The simulation results showed that due to differences in material properties,the effect of extrusion temperature on the bonding performance of extruded bimetallic materials was reflected in multiple aspects,such as atomic diffusion energy and flow stress differences during extrusion.The hardness test results indicated that reasonable control of extrusion temperature could reduce the thickness of the bonding layer while improving the hardness of the matrix material.Mg/Al bimetallic composite tubes prepared by direct extrusion expanded shear deformation(DEES)process have good adhesion,and the bonding interface is free from defects and cracks.The thickness of the bonding layer is the lowest at 390 and the highest at 420.During extrusion at 390,the hardness of the su℃℃℃bstrate is the highest.It is necessary to control the extrusion temperature reasonably to obtain better composite pipes.The DESS process can effectively refine grains and ultimately form uniform and fine equiaxed grains.