Mg-6Al-2Sr-xY镁合金的显微组织和力学性能

Microstructure and Mechanical Properties of Mg-6Al-2Sr-xY Magnesium Alloys

采用氩气保护的方法制备了Mg-6Al-2Sr-xY镁合金,研究了钇含量对该合金显微组织和力学性能的影响,探讨了锶和钇在合金中的存在形式。结果表明:加入适量的钇能使该合金的铸态显微组织明显细化,锶和钇在合金中主要以Al4Sr、Al2Y和Al3Y形态存在,Al4Sr相呈骨骼状分布于晶界处,Al2Y和Al3Y呈颗粒状主要在晶内析出;合金的力学性能随着钇含量的增加呈现先上升后下降的趋势,当钇质量分数为1.5%时,与Mg-6Al-2Sr镁合金相比,该合金的抗拉强度提高了20.6%,屈服强度提高了24.6%,伸长率提高了52.9%。

A series of Mg-6Al-2Sr-xY magnesium alloys were prepared under the protection of argon atmosphere. The effect of Y content on microstructure and mechanical properties ofMg-6Al-2Sr-xY was studied and the existing forms of Y and Sr in the alloy were discussed. The results indicate that the proper addition of Y resulted in the refinement of Mg-6Al-2Sr-xY alloy microstructure. Sr and Y exsited in the forms of AI4 St, Al2 Y and Al3 Y phas. Net-like Al4 Sr phase was distributed along the grain boundary and particle-like or acicular Al-Y phase was mainly precipitated from the grain. The mechanical properties of the alloys initially ascended and then descended with the increase of Y addition. When Y content was 1. 5wt%, compared with Mg-6Al-2Sr alloy, the tensile strength of the alloy was improved by 20. 6%, yield strength was increased by 24. 6% and the elongation was enhanced by 52. 9%.