机加工材料Al-Si-Mg合金超塑性变形及微观组织研究

Research on Superplastic Deformation and Microstructure of Machining Material Al-Si-Mg Alloy

以新型机加工材料Al-Si-Mg合金铸件为研究对象,在Instron5500电子万能材料试验机上进行超塑性拉伸试验,研究了合金在不同温度和应变速率下的超塑性变形及合金微观组织。结果表明,随着温度升高,合金的伸长率和真应力不断增加,应变速率敏感指数也随着增加,合金流动活化能不断减小,合金超塑性变好;在合金挤压过程中,铸态合金中含有纤维球状的共晶硅颗粒,随着热处理的不断进行,共晶硅颗粒不断细化且均匀分布,横向截面的共晶硅颗粒比纵向截面的共晶硅颗粒密集,经过人工时效处理后,合金中共晶硅颗粒不断增加,强度不断增加,伸长率逐渐减小。

Taking new machining material of A1-Si-Mg alloy forging as research object, the superplastic tensile experiments in Instron5500 electronic universal material testing machine was conducted.The superplastic deformation and microstructure of the alloy at different temperature and strain rate were researched. The experimental results show that with the increase of temperature, the true stress and elongation of the alloy increases, the strain rate sensitivity index also increases, as the alloy flow activation energy of the alloy decreases continuously, the superplastic of alloy is better;in alloy extrusion process, the as-cast contains fiber spherical eutectic silicon particles, with the development of heat treatment on eutectic silicon particles in continuous refinement and uniform distribution, the transverse section of the eutectic silicon particle is more intensive than the longitudinal section of the eutcctic silicon particles, after artificial aging treatment of the alloy, the alloy particles increase, the strength increases, and the elongation decreases.