稀土Ce变质铸造Al-12.35Si合金的组织及性能

Microstructure and Properties of Rare Earth Ce Modified Cast Al-12.35Si Alloy

以添加Al-Ce稀土中间合金的方式对Al-12.35Si合金进行变质处理,研究Ce的添加量(0〜0.8%)对合金微观组织和力学性能的影响规律。结果表明,添加适量的Ce可以减小共晶硅的尺寸,细化第二相,减小α-Al二次枝晶臂间距,提高合金的力学性能。但是当Ce的添加量超过0.2%时,会出现过变质现象,导致合金组织粗化,降低合金的力学性能。当Ce的添加量为0.2%时,Al-12.35Si合金的变质效果最为理想且得到了最优的力学性能,与未变质的Al-12.35Si合金相比,变质后,合金的抗拉强度从168 MPa提升到223 MPa,伸长率从0.44%提高到0.72%。

Al-12.35Si alloy was modified by adding Al-Ce rare earth master alloy.The effect of Ce content(0~0.8%)on microstructure and mechanical properties of as-cast Al-12.35Si alloy was studied.The results show that adding appropriate amount of Ce can reduce the size of eutectic silicon,refine the second phase,reduce the secondary dendrite arm spacing of a-Al,and improve the mechanical properties of the alloy.However,when the addition of Ce is more than 0.2%,the over-metamorphism will occur,which leads to the coarsening of the alloy microstructure and reduces the mechanical properties of the alloy.When Ce content is 0.2%,the modification effect of Al-12.35Si alloy is ideal and the best mechanical properties are obtained.Compared with the unmodified Al-12.35Si alloy,the tensile strength of the modified alloy is increased from 168 MPa to 223 MPa,and the elongation is increased from 0.44%to 0.72%.