Physical and mechanical properties of 7075 sheets produced by EP electro- and electromagnetic cast rolling

摘要

In this study the effect of twin-roll casting (TRC) producing conditions on microstructure and mechanical properties of Al-7075 alloys has been investigated in detail. When introducing an electric pulse (EP) of 400 I peak current and 30 Hz into the conventional TRC process, the dendrites are refined and equiaxed accompanied by thick segregation bands beingabated. The most uniform structure of 7075 alloy is obtained after applying a static magnetic field of 0.2 T at the same time. EDS spectrum analysis shows that the netlike T (AlZnMgCu) phase is resolved while the mixture of η (MgZn_2) and CuMg_2 phases improves. Moreover the increase in solute diffusivity is due to the modification of heat and mass convections by the incoming EP energy, facilitating the realization of excellent mechanical properties. The tensile tests reveal that the optimum process, in which the highest strength and ductile manner were obtained, is considered to be EP electromagnetic TRC modification.