Ce和Cu复合合金化对A356.2合金组织和力学性能的影响

Effect of Ce and Cu Composite Alloying on Microstructure and Mechanical Properties of A356.2 Alloy

利用光学显微镜、扫描电镜、X射线衍射仪、室温拉伸试验机等研究了Ce和Cu复合合金化对A356.2铝合金组织和力学性能的影响。结果表明,在单独添加Ce时,随着Ce含量的增加,A356.2铝合金中的α-Al相得到不同程度的细化,在添加0.1%的Ce时,合金中α-Al相的二次枝晶臂间距最小为29.6μm,其抗拉强度最佳,为310.8 MPa。因此选用0.1%Ce和不同含量的Cu来研究其对A356.2合金组织和力学性能的影响,随着Cu含量增加,A356.2合金中α-Al相得到细化,共晶Si得到有效的变质,并且出现新的Al_(2)Cu和Al_(8)Cu_(4)Ce相,起到固溶强化和弥散强化的作用,提高了合金的强度。在添加1.5%Cu和0.1%的Ce后,A356.2铝合金力学性能最好,抗拉强度为350.75 MPa,屈服强度为273.80 MPa,延伸率为6.52%。

Effect of Ce and Cu composite alloying on microstructure and properties of A356.2 alloy was investigated by means of optical microstructure,scanning electron microscopy,X-ray diffraction and room temperature tensile tests.The results show that with the increase of Ce content,theα-Al phase was refined in varying degrees.When the addition of Ce was 0.1%,theα-Al phase was refined in the alloy and the minimum secondary dendrite arm spacing ofα-Al phase is 29.6μm.Its best tensile strength is 310.8 MPa.Therefore,0.1%Ce and different contents of Cu were selected to studied the effect on microstructure and mechanical properties of A356.2 alloy.With the increase of Cu content(The Ce content is kept at 0.1%),α-Al phase in A356.2 alloy is refined,eutectic Si is effectively modified,and new Al_(2)Cu and Al_(8)Cu_(4)Ce phases appear,which plays the role of solid solution strengthening and dispersion strengthening,and improves the strength of the alloy.After adding 1.5%Cu and 0.1%Ce,A356.2 aluminum alloy has the best mechanical properties,the tensile strength is 350.75 MPa,the yield strength is 273.80 MPa,and the elongation is 6.52%.