AlSi7Mg合金双级时效工艺研究

Study on Two-stage Aging Process of AlSi7Mg Alloy

研究了双级时效热处理工艺对AlSi7Mg合金组织与性能的影响。对试样进行535℃×10 h固溶处理、120℃不同保温时间预时效和不同温度终时效的双级时效工艺与传统热处理的对比试验。结果显示:合金的抗拉强度最高提升5%,伸长率最高提升20%。AlSi7Mg合金经过预时效处理后,有利于GP(Ⅰ)区形核数量的增加,终时效时形成更多细小弥散分布的稳定相(Mg_2Si),材料抗拉强度得到提升,晶界处均匀分布的共晶Si更加细小、圆整,有利于材料伸长率的提高。

The effect of two-stage aging heat treatment on the microstructure and properties of Al Si7Mg alloy was studied.The two-step aging process was solution treatment of 535℃for 10 h,pre-aging process treatment of 120℃for different aging time and final aging process of different aging temperature for 5 h,the results show that the tensile strength and elongation of the alloy after two-stage process treatment increase by 5%and 20%compared with that of the conventional solution aging heat treatment,respectively.The better ultimate strength of the after two-stage aging alloy is attributed to more fine dispersed second phase(Mg2Si)due to the increasing number of GP(Ⅰ)area during pre-heat treatment,meanwhile,the fine and round silicon phase dispersively distributed at the grain boundary can improve the elongation of the alloy.