Mg含量对体育器材用Al-6Zn-xMg-0.5Cu-0.1Zr铸造铝合金组织及性能的影响

Effect of Mg Content on Microstructure and Properties of Al-6Zn-xMg-0.5Cu-0.1Zr Casting Alloy for Sports Equipment

采用金属型铸造工艺制备了体育器材用Al-6Zn-xMg-0.5Cu-0.1Zr(x=1.4-2.6)铝合金,研究了Mg含量对其组织和性能的影响。研究发现,随着Mg含量的增加,铸态下合金的晶粒尺寸逐渐减小,第二相主要由连续网状的MgZn相和弥散分布的圆形AlMgCu相组成。热处理后,第二相大部分固溶于基体中,只有少量时效析出相以细小的长条状弥散分布在基体中,但是当Mg含量到2.6%时,合金中仍然存在大量第二相。T6热处理后合金的拉伸强度和屈服强度随着Mg含量的增加先增加后减小,当Mg含量为2.0%时,拉伸强度和屈服强度较高,分别为470.8 MPa和218.9 MPa,相比于Mg含量为2.6%的试样分别提高了21.2%和13.3%。

In this paper,Al-6Zn-xMg-0.5Cu-0.1Zr aluminum alloy for sports equipment was prepared by the permanent mold casting,and the effect of Mg content on its microstructure and properties was studied.It was found that the grain size decreased gradually with the increase of the Mg content at the as-cast,and the second phases were mainly composed of the continuous meshy MgZn_(2) phase and the dispersed and circular Al_(2)MgCu.After heat treatment,most of the second phases were solidly dissolved into the matrix,and only a few aging precipitated phases were dispersed in the matrix in fine strips.However,with the Mg content reaching 2.6%,there were still a large amount of residual precipitated phases in the matrix.The tensile strength and yield strength of the alloy increased firstly and then decreased with the increase of the Mg content continuously.When the Mg content was 2.0%,the tensile strength and yield strength were high and reached the values of 470.8 MPa and 218.9 MPa,respectively,which were 21.2%and 13.3%higher than that with 2.6%Mg content,respectively.