中文摘要：

采用亚共晶ZL101铝合金,研究了不同超声波导入条件下半固态浆料组织演化过程.结果表明,导入超声波时的温度对浆料初生晶粒的形貌影响明显.从640℃开始导入超声波,初生晶粒保持以近球状形式生长;熔体降温至610℃（固相率达0.1后）再导入超声波,初生晶粒逐渐由枝晶向非枝晶转化,120S后初生晶粒粒状化;冷却至600℃（固相率近0.25后）再导入超声波,最终组织为粒状晶和枝晶混合组织.最后对超声场中半固态浆料组织演化机理进行了分析讨论.

英文摘要：

The microstructural evolution of semisolid ZL101 hypoeutectic ANSi alloy solidified in ultrasound field was investigated. The results indicate that the morphology of primary particles is related closely to the temperature of the applied ultrasound field. The primary grains grow into globular shape when ultrasound is applied from 640 to 585 ℃（nearly solidified temperature）. When the ultrasound is applied from 610 （solid fraction 0.1） to 598 ℃ （applied 120 s）, the originally formed dendrites are granulated. When the ultrasound is applied at 600 ℃ （solid fraction 0.25） and holding temperature for 120 s （about 595 ℃）, a mixture structure consisted of dendrite and granulated grains is formed. The evolution mechanism of semisolid microstructure under ultrasound field was discussed.