中文摘要：

采用光学显微镜、阿基米德法、扫描电镜及电子探针等手段研究了熔体经400W超声处理对7050铝合金铸锭中的气孔、密度、显微组织及成分分布等的影响。结果表明：超声处理具有良好的除气和细化效果，随着超声处理时间的延长，7050铝合金铸锭的气孔数量先减少后又增多，而铸锭密度先增大后又减小，铸态显微组织先细化后又粗化；超声处理90S时，除气和细化效果最好，可获得基本元气孔的致密铸态组织；超声处理还可使合金的晶间第二相更细小，成分分布更均匀。

英文摘要：

The effect of melt ultrasonic treatment （400 W） on the pores, microstructure and as-cast component distribution of 7050 aluminium alloy was studied by metalloscopy, Archimedes＇ method, scanning electron microscopy and electron probe micro analysis. Te results indicate that good degassing and refinement results could be obtained after the melt was treated by ultrasonic. As the ultrasonic treatment time was prolonged, the pores in the ingot decreased at first and then increased, while the density of the ingot increased at first and then decreased. The as-cast microstructure was refined at first and then was coarsened. When it was treated by ultrasonic for 90 s, the degassing and refinement effects were the best, a compact as-cast microstructure with no pore could be obtained. Ultrasonic treatment could also reduce the formation of second-phases at grain boundaries and make the component distribution more uniform.