Effect of Heat Treatment Process on Microstructure and Properties of Al-10%Si-3%Cu-0.3%Mg Alloy

The effects of heat treatment on the microstructure and mechanical properties of Al-10%Si-3%Cu-0.3%Mg alloy were investigated.The hardness and tensile strength of the alloy were studied through observing the microstructure,detecting the mechanical properties and analyzing the fracture morphology.The results show that after solution treatment at 500 ℃(or 500 ℃ × 4 h+515 ℃),the dissolution of the copper rich phases increases against the time,and melting of the copper rich phases is observed at 535 ℃ solution temperature.And compared with the single-step solution treatment,the copper rich phases is ample dissolution and the mechanical properties are better.After solution treatment at 500 ℃for 8 h and then solution treatment at 515 ℃ for 8 h,the mechanical properties are best;and further after aging at 175 ℃ for 4 h,the tensile strength and ductility are obviously improved.