固溶处理对半固态7075铝合金浆料组织的影响

Influence of Solution Treatment Process Parameters on Semi-Solid 7075 Al Alloy Slurry

摘要: 本文采用锥形管浇注流变成形技术制备了半固态7075铝合金浆料，并研究了不同的固溶处理工艺对浆料组织的影响规律。结果表明，当固溶温度在460~475℃之间，固溶时间在1~6 h时，随着固溶温度的提高和固溶时间的延长，浆料组织中的第二相粒子逐渐的溶入基体中，初生晶粒的合并和长大现象并不明显。当固溶温度超过490℃时，组织中出现了较多的晶粒重熔及过烧现象，并出现了较多的晶粒异常长大和合并。晶粒的异常长大主要是由于组织中的晶界析出相在较高固溶温度下的快速溶解。当固溶温度为475℃时，随着固溶时间的延长，组织中的第二相粒子的溶解现象更加明显。

Abstract: The semi-solid slurry of 7075 aluminum alloy was prepared by inverted cone-shaped pouring channel process, and the influence of process parameters on the microstructure evolution of 7075 aluminum alloy slurry during solution treatment was investigated. The results shows that when the solution temperature was between 460˚C - 475˚C, and the solution time was between 1 h - 6 h, as the solution temperature and solution time increased, the dissolution of secondary phase particles in the matrix of slurry was significantly enhanced, and the size of the primary α-Al was still small with a slightly reduce of shape factor. When the solution temperature was above 490˚C, the size of the primary α-Al was significantly enhanced and the grain remelting appeared. The increase in grain growth rate was ascribed to the dissolution of secondary phase particles, whose inhibiting effect on grain boundary migration decreased. When the solution temperature was 475˚C, as the solution time increased, the dissolution of secondary phase particles was more obvious.