中文摘要：

研究了波浪型倾斜板振动过程中Al-6Si-2Mg合金的组织演化规律和球形晶组织的形成机理.结果表明：Al-6Si-2Mg合金的非枝晶组织形成过程主要受到两种机制的作用.第一种机制是熔体爆发形核和球状长大机制：倾斜板为形核提供了足够大的过冷度和异质形核基础,使熔体爆发形核,熔体均匀的成分场和温度场使部分晶粒球状生长;第二种机制是枝晶臂颈缩断裂和磨圆热化机制：流动和振动使晶粒低熔点处颈缩断裂,断裂晶粒不断磨圆熟化形成近球形组织.

英文摘要：

Metalloscope and energy spectrometer were adopted to study microstructure evolution and mechanism of spherical grain formation of Al-6Si-2Mg alloy during vibrating wavelike sloping plate process. The results show that the coactions of two mechanisms cause non-dendrite microstructure formation. The first mechanism is eruptive nucleation and globular growth： sloping plate can provide enough undercooling degree and substratum for the heterogeneous nucleation, so the melt can eruptive nucleate on the surface of the sloping plate. The distributions of composition and temperature fields homogeneous in the melt lead grain to grow with a globular pattern. The second mechanism is dendrite arm necking and breaking and grain grinding and growing： flowing and vibrating in the melt leads to neck and break at the positions enrich compositions of low melting point. Broken grains gradually grow to spherical grains under grinding.