Influence of Mn and Mg contents on mechanical properties of the die-casting aluminum alloy HL-111

Abstract

In this study, four groups of thin plate samples with a wall thickness of 2.2mm, 2.5mm, 2.7mm, and 3.0mm are prepared by ultra-high vacuum die casting. The effects of Mn, Mg, and Mn/Mg ratio on the microstructure and mechanical properties of samples with different wall thicknesses are obtained by different test and analysis methods. The results show that as the content of Mn is 0.4% ～ 0.65%, the content of Mg is 0.17% ～ 0.5%, and the Mn / Mg ratio reaches 1.69 ～ 1.90, the tensile strength, yield strength, and elongation of HL-111 alloy with a wall thickness of 2 ～ 3mm can reach more than 280MPa, 120MPa and 10% respectively, and the mechanical properties of the material are greatly improved. In addition, the tensile strength, yield strength, and elongation of HL-111 alloy after T5 heat treatment at 165 ℃ for 510min reach 302.36 MPa, 190.32 MPa, and 8.42%. The precipitated phase of Mg2Si leads to changes in strength and elongation.