Sc 和 Zr 对挤压铸造 ZL205A 合金组织与性能的影响

The effects of Sc and Zr contents on microstructure and mechanical properties of squeezing casting ZL205A alloy were investigated. The results indicate that with the mass fraction of Sc element increasing，the grain structure of alloy is refined and the tensile strength is increased firstly and then decreased. When the mass fraction of Sc element is 0.40%，the tensile strength，elongation and hardness of alloy reach 389.5 MPa，14.8% and 122.9 HV，respectively. Simultaneous addition of Sc and Zr elements has significant improvement on microstructures and mechanical properties of alloy. With 0.40% Sc and 0.15% Zr addition，the tensile strength and elongation of alloy at room temperature reach 398.3 MPa and 15.7%，respectively. After T5 heat treatment，the tensile strength and elongation of alloy at 150 ℃ reach 345.1 MPa and 15.8%. The connecting rod component with satisfied surface quality was successfully fabricated by squeezing casting with modified ZL205A alloy. The tensile strength，elongation and hardness of connecting rod reach 468.6 MPa，15.2% and 146.6 HV，respectively.