Grain refinement and mechanical property of Al-Cu-Mg-Si-Ti-Sc alloy in the state of deformation treatment condition

Abstract

Al-Cu-Mg-Si-Ti-Sc compound metal with distinct content of Sc increment was prepared by using metallurgical engineering processing. The formation of Sc in Al-4.5%Cu-1.3%Mg-0.6%Si-0.2%Ti-xSc compound metal and its microstructural observation was studied with SEM. The mechanical performances of the compound metal were measured by tensile and fatigue tests in the state of machining distortion conditions. The result reveals that the increment of 0.2% rare earth Sc can fine Al-Cu-Mg-Si-Ti-Sc compound metal grain crystals, which enhances ordinary temperature tensile strength, yield strength, and elongation. The low cycle fatigue of Al-5.2Mg-0.8Si-0.25Cr-0.1Zr-0.2Sc compound metal reveals a cyclic steady state, which mainly relies on the amplitude of the density of movable dislocations and gross applied strain during cyclic distortion. Meanwhile, under external action, the dislocation slip is more in-homogeneous, and materials are more prone to trans-granular crack in which grain crystals can coordinate distortion.