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研究了加热温度和保温时间对部分重熔再结晶方法(RAP)制备7075铝合金半固态坯料过程中的组织演变的影响。结果表明,通过在半固态温度区间加热可以将挤压态7075铝合金的纤维组织转变为半固态颗粒状晶粒组织。随着加热温度的提高和保温时间延长,挤压态组织逐渐消失,颗粒状晶粒经再结晶生长并合并长大;颗粒状晶粒的尺寸随加热温度和保温时间的增加而变大。在试验条件下,高温短时间加热比低温长时间下获得的半固态组织更加细小均匀。通过试验得出RAP法制备7075铝合金半固态坯料的优化工艺参数为600℃下保温5min。
The effects of heating temperature and holding time on the microstructure evolution of 7075 aluminum alloy semi-solid billet prepared by partial remelting recrystallization (RAP) were studied. The results show that the microstructure of extruded 7075 aluminum alloy can be transformed into semi-solid granular grain structure by heating in the semi-solid temperature range. With the increase of heating temperature and holding time, the microstructure of extruded state gradually disappeared. The granular grains grew and recrystallized to grow together. The size of granular grains became larger with the increase of heating temperature and holding time. Under the experimental conditions, the heating at a high temperature for a short time is more even and more uniform than the semi-solid structure obtained at a low temperature for a long time. The optimum technological parameters of 7075 aluminum alloy semi-solid billet prepared by RAP method are obtained through experiments.