Post-treatment Process of Semi-solid Powder Rolling

作者:Luo, Xia; Liu, Yun-Zhong*; Wang, Bin
来源:Acta Metallurgica Sinica (English Letters), 2015, 28(10): 1305-1315.
DOI:10.1007/s40195-015-0327-4

摘要

Semi-solid powder rolling is a strip manufacturing process, which combines powder rolling with semi-solid rolling in one step to prepare high-performance metallic strips. A total of 7050 aluminum alloy strips were prepared by semi-solid powder rolling and then used to study the post-treatment process and evaluate qualities of post-treated strips. Three post-treatment processes involving sintering, pre-sintering cold deformation sintering, and hot rolling were used to process the semi-solid powder rolled strips. The results show that both swelling of pores and densification occur during solid-state sintering while microhardness increases. The decrease in density is due to that the swelling of pores has a larger effect on the density change than that of densification. The relative density reaches 92.6% with the maximum microhardness of 300 HV after "pre-sintering cold deformation sintering" process. High microhardness is due to the ultrafine secondary particles uniformly distributed within the grains. The microhardness and relative density of a hot rolled strip are 176 HV and 99%, respectively, and the secondary particles disappear. Occurrence of recrystallization in these three post-treatment processes makes the grains finer.