镁基准晶对AM50合金组织与性能的影响

Effect of Mg-Based Quasicrystals Addition on Microstructure and Mechanical Properties of AM50 Magnesium Alloy

摘要:

通过普通凝固方法制备含高体积分数准晶相的Mg-48Zn-13Y准晶中间合金。利用OM,SEM,EDS,XRD及拉伸实验研究了MZY准晶对AM50合金显微组织及力学性能的影响。结果表明：向AM50合金中添加MZY准晶后,组织中可保留Mg₃Zn₆Y准晶相,并使合金组织得到明显地细化；组织中β-Mg₁₇Al₁₂相的数量减少,且形貌由粗大连续网状向断续条状及颗粒状转变。其中,当MZY准晶加入量为6%时,合金组织最为细小,合金的抗拉强度、屈服强度及伸长率达到峰值,分别为202.92MPa、100.57MPa和10.8%,其比AM50合金分别提高了24.59%、74.9%和66.15%。外加MZY准晶改善AM50合金力学性能的原因可归结于组织细化、β-Mg₁₇Al₁₂相数量及形貌的改善、以及与镁合金基体具有良好润湿性的准晶相的弥散强化作用。

Abstract:

The Mg-48Zn-13Y quasicrystal master alloy with high volume fraction of the quasicrystalline phase was prepared by conventional solidification method. The influences of the MZY quasicrystal on microstructures and properties of AM50 alloys were investigated by OM, SEM, EDS, XRD and tensile tests. The results indicated that addition of the MZY quasicrystal to AM50 alloy, the Mg₃Zn₆Y quasicrystal phase could be left well in AM50 matrix alloy, and the microstructures were obviously refined. The β phase in the microstructures was changed from coarse and continuous to discontinuous strip and granular, and the amount was decreased. When the content of the MZY quasicrystal is up to 6%, the microstructure was greatly refined, and the ultimate tensile strength, yield strength and elongation of the alloy reached to the maximum, 206.63 MPa, 92.50 MPa and 10.04%, respectively. Compared with AM50 alloy, it is improved by 24.59%, 74.9% and 66.15%, respectively. Mechanical properties of AM50 magnesium alloy can be improved significantly by addition of the MZY quasicrystal, which results from the microstructure refinement, the optimization of the morphology and amount of the β phase and the dispersion strengthening effect of the quasicrystal phase has good wettability with the magnesium alloy substrate.