Sc和Zr对挤压铸造ZL205A合金组织与性能的影响

Effects of Sc and Zr on Microstructures and Mechanical Properties of Squeezing Cast⁃ing ZL205A Alloy

研究了Sc和Zr含量对挤压铸造ZL205A铝合金微观组织和力学性能的影响。结果表明,随着Sc含量增加,合金基体晶粒组织细化,抗拉强度先升高后降低,当Sc含量为0.40%(质量分数,下同)时,铝合金的抗拉强度、伸长率和硬度(HV)分别为389.5 MPa、14.8%和122.9。同时添加Sc和Zr对合金组织的细化和力学性能的提升效果更显著,当添加0.40%的Sc和0.15%的Zr时,合金在室温下的抗拉强度和伸长率分别达到398.3 MPa和15.7%;经过T5热处理后,合金在150℃下的抗拉强度为345.1 MPa,伸长率为15.8%。对Sc和Zr元素改性的ZL205A铝合金采用挤压铸造制造了连杆构件,表面质量良好,构件最高抗拉强度和伸长率分别为468.6 MPa和15.2%,硬度(HV)最高为146.6。

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.