Mechanical Properties of Cast Al-Mg 5 Alloy Produced by Heated Mold Continuous Casting

摘要

Abstract To make the high strength and high ductility of the cast aluminum alloys, the Al alloy samples are created by the heated mold continuous casting (HMC) process. Because of the rapid and unidirectional solidification in the HMC process, tiny grains with uniformly orientated crystals are created. In this case, influence of the solidification speed of HMC on the mechanical properties of the Al-Mg-based alloy is studied. The microstructures are altered with the casting speed because of the different solidification rates. The mean secondary dendrite arm spacing (SDAS) for the HMC-Al-Mg alloy made at the high casting speed of 2.7?mm/s is about one-fifth of that for the conventional gravity cast Al-Mg alloy. Nonlinear relationship between the tensile properties (strength and ductility) and the cooling rate are obtained with σ ~(UTS)and σ ~(0.2)increasing and ε ~(f)decreasing with increasing the cooling rate. The high strength of the HMC samples at the high cooling rate results from the existence of tiny microstructures. The high ductility of the HMC sample at the low cooling rate is affected by the uniform crystal orientation, where shear slips are facilitated by the uniform crystal orientation.