Effects of Zn and RE on Microstructure and Properties of AlMgSiCu Alloy

By analyzing the action of rare earth and zinc in AlMgSiCu alloy, it is found that the increasing of zinc can lead the content of Al in the alloy to decrease, to reduce the tendency to form Al-Cu compound, and increase the copper-rich phase of CuZn2, so that the tensile strength and hardness of the alloy improve. It is confirmed that the refinement of RE in high zinc aluminum alloy exist, but the acicular RE compounds appear in the alloy if adding excessive RE in high zinc aluminum alloy, it is bad for the alloy. When adding 0.2% Re and 7.5% Zn to the alloy, there are no obvious needle RE phase in the alloy, which is best for the comprehensive performance of alloy, the tensile strength of 343.14 MPa and hardness of 112.3 HB,the first alloy increased by 10.2% and 2.7% compared with 1# alloy, only the elongation decreases by 17.5%.