汽车发动机用铝硅合金的半固态成形工艺

Semi-solid forming technology of aluminum silicon alloy for automobile engine

采用斜坡法制备了Al-20Si-3Fe合金坯料,并对合金坯料进行二次加热、触变成形和固溶时效处理,研究了二次加热温度和保温时间对半固态合金坯料组织的影响,并对比分析了触变成形和固溶时效处理对合金组织与性能的影响。研究结果表明,Al-20Si-3Fe合金适宜的二次加热工艺为:加热温度580℃,保温30 min;3种状态下合金的强度和硬度顺序从高到低依次为:热处理态>触变成形>铸态,其中,热处理态和触变成形态合金的塑性相当,且都高于铸态合金。

Alloy Al- 20Si -3Fe billets were prepared by slope method and reheating, thixoforming and solution and aging treatment. Furthermore, it was studied that the influences of second heating temperature and holding time on the microstructure of semi-solid alloy billets, and the comparative analysis was carried out according to the influence of thixoforming and solution and aging treatment on properties and microstructure of alloy. The results show that the suitable second heating technology of alloy Al -20Si -3Fe is the heating temperature 580 ℃ and the holding time 30 rain. The hardness and strength sequence of three kinds of alloys is that heat treatment state 〉 thixoformed state 〉 casting state, and the plasticity of alloy Al-20Si -3Fe after heat treatment and thixoforming are equal, both of which are higher than that of cast alloy.