超声预处理对ZL205A铝合金铸件凝固组织的影响

摘要

在液相线以上不同的温度对ZL205A铝合金熔体施加超声预处理后进行浇铸,研究在液相高温区段对ZL205A铝合金熔体施加超声预处理后对其铸件凝固组织的影响,探索超声预处理ZL205A铝合金熔体对其铸件凝固组织影响的作用机制.研究结果表明:超声波作用于ZL205A铝合金熔体高温液相区段能有效减少其铸件凝固组织的气孔,细化其铸件的凝固组织,且这种细化效果随着超声施振温度的提高而减弱.超声空化促进Al3Ti的形成和分布,提高形核率是超声预处理ZL205A铝合金熔体改善其铸件凝固组织的主要机制.%In order to study the influence of ultrasonic pretreatment(UT) of ZL205A aluminum alloy melt in high temperature range on the casting microstructures and its mechanism,ultrasonic treatment was applied in the molten ZL205A aluminum alloy in different temperature ranges above its liquidus. The results show that UT applied in the molten ZL205A aluminum alloy at different temperatures above its liquidus can effectively reduce the porosity in its solidification structure, refine its casting microstructure and the refinement is gradually weakened by increasing the temperature of applying ultrasonic vibration. Ultrasonic cavitation/assists the formation and distribution of Al3Ti and increases the nucleation rate, which is the main mechanism of refining casting solidification structure after ultrasonic pretreatment of molten ZL205A aluminum alloy.