坯料预热方式对AZ80镁合金轮毂组织和性能的影响

Influence of billet preheating method on microstructure and properties for AZ80 magnesium alloy wheel hub

采用对比的方法,研究了经过410℃/23 h的均质化处理后,直接锻压和再热锻压对轮毂组织和性能的影响。结果表明:均质化处理后直接锻压可以提高生产效率、节约能源,锻压后轮毂的表面质量较好,无表面裂纹和折叠等锻压缺陷,但是其力学性能明显低于均质化处理后再热锻压的轮毂,而且显微组织中晶粒大小不均匀,晶界上的再结晶晶粒细小,晶内的单相固溶体比较粗大;而均质化处理后,经过435℃/7.5 h的锻前再热处理后锻压获得的轮毂的组织均匀细小、晶界细,存在明显的锻压织构,轮毂各部位的力学性能均高于均质化处理后直接锻压的轮毂的力学性能,尤其是轮辋、轮辐部位的力学性能相差较大。

The influences of direct forging and hot forging after 410 ℃/23 h homogenization treatment on the microstructure and properties of wheel hub were studied by means of contrast. The results show that the direct forging after homogenization treatment can improve production efficiency and save energy, the surface quality of wheel hub after forging is better, and there are no forging defects such as surface cracks and folding. However, its mechanical properties are obviously lower than those of the wheel hub after homogenization treatment and hot forging, the grain size is not uniform in the microstructure, the recrystallized grain is small on the grain boundary, and the single-phase solid solution in the grain is relatively coarser. After the homogenization treatment, the microstructure of the forged wheel hub after re-heat treatment at 435 ℃ for 7.5 h before forging is uniform and fine with fine grain boundary and obvious forging texture. The mechanical properties of all parts for the wheel hub are higher than those of the wheel hub that is homogenized treatment and then directly forged, especially, the mechanical properties of rim and spoke are different greatly.