Mg-Sc-Y三元合金的微观组织和力学性能
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摘要
稀土元素作为重要的镁合金强化相元素,其多元添加产生的影响并未得到充分研究。在Mg-Sc二元系的基础上将Y作为第三元加入,制备了Mg-5Sc二元合金及Mg-5Sc-0.5Y,Mg-5Sc-1Y,Mg-5Sc-2Y,Mg-5Sc-3Y,Mg-5Sc-3.5Y(质量分数,%)5种三元合金,并通过光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射(XRD)及室温拉伸等试验,研究了Y元素的加入对Mg-Sc二元合金微观组织和力学性能的影响。结果表明:Y元素在合金中的主要存在形式为固溶态,富集于晶界处。随着Y元素含量的提升,合金晶粒度显著减小,屈服强度和硬度大幅提升,Mg-5Sc-3.5Y的屈服强度相比Mg-5Sc提升了约50%。该强度的提升主要是由细晶强化和固溶强化引起的。
Rare earth is an important strengthening phase element in magnesium alloy. However, the effect of multi-component addition has not been fully studied. In this paper, Y is added as a third element based on the Mg-Sc binary system. Mg-5 Sc binary alloy and Mg-5 Sc-0.5 Y, Mg-5 Sc-1 Y, Mg-5 Sc-2 Y, Mg-5 Sc-3 Y, Mg-5 Sc-3.5 Y are prepared, and the influence of Y on the microstructure and mechanical properties of the binary alloy is studied by optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffraction(XRD) and room temperature tensile test. The results show that solid solution state is the main form of Y in the alloy, which is rich at the grain boundary. As Y content increases, the grain size decreases significantly. In the mechanical property test, it is found that the addition of Y in the solid solution state can significantly improve mechanical properties and hardness of the Mg-Sc alloy, e.g. the yield strength of the alloy increases from 70 MPa of Mg-5 Sc to 109 MPa of Mg-5 Sc-3.5 Y. This phenomenon is mainly due to the combination of fine grain strengthening and solid solution strengthening.
Rare earth is an important strengthening phase element in magnesium alloy. However, the effect of multi-component addition has not been fully studied. In this paper, Y is added as a third element based on the Mg-Sc binary system. Mg-5 Sc binary alloy and Mg-5 Sc-0.5 Y, Mg-5 Sc-1 Y, Mg-5 Sc-2 Y, Mg-5 Sc-3 Y, Mg-5 Sc-3.5 Y are prepared, and the influence of Y on the microstructure and mechanical properties of the binary alloy is studied by optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffraction(XRD) and room temperature tensile test. The results show that solid solution state is the main form of Y in the alloy, which is rich at the grain boundary. As Y content increases, the grain size decreases significantly. In the mechanical property test, it is found that the addition of Y in the solid solution state can significantly improve mechanical properties and hardness of the Mg-Sc alloy, e.g. the yield strength of the alloy increases from 70 MPa of Mg-5 Sc to 109 MPa of Mg-5 Sc-3.5 Y. This phenomenon is mainly due to the combination of fine grain strengthening and solid solution strengthening.
引文
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[12] 张曼玉,应韬,曾小勤,等.Mg-Sc二元合金微观组织和力学性能研究[J].铸造技术,2018(5):947-951.
[13] 雷维维,梁伟,黄志军.热挤压后纯镁的组织与力学性能研究[J].热加工工艺,2016,45(23):125-127.
[2] LU Y,TAHERI F,GHARGHOURI M A,et al.Experimental and numerical study of the effects of porosity on fatigue crack initiation of HPDC magnesium AM60B alloy[J].Journal of Alloys & Compounds,2009,470(1):202-213.
[3] 樊昱,吴国华,高洪涛,等.Ca对镁合金组织、力学性能和腐蚀性能的影响[J].中国有色金属学报,2005,15(2):51-57.
[4] 孙扬善,翁坤忠.Sn对镁合金显微组织和力学性能的影响[J].中国有色金属学报,1999(1):55-60.
[5] CAO F,SHI Z,SONG G L,et al.Corrosion behaviour in salt spray and in 3.5% NaCl solution saturated with Mg (OH)2,of as-cast and solution heat-treated binary Mg-X alloys:X=Mn,Sn,Ca,Zn,Al,Zr,Si,Sr[J].Corrosion Science,2013,76(11):60-97.
[6] BUCH F V,LIETZAU J,MORDIKE B L,et al.Development of Mg-Sc-Mn alloys[J].Materials Science and Engineering A:Structural Materials Properties Microstructure and Processing,1999,263(1):1-7.
[7] NIE J F,MUDDLE B C.Precipitation in magnesium alloy WE54 during isothermal ageing at 250 ℃[J].Scripta Materialia,1999,40(10):1089-1094.
[8] ANTION C,DONNADIEU P,PERRARD F,et al.Hardening precipitation in a Mg-4Y-3RE alloy[J].Acta Materialia,2003,51(18):5335-5348.
[9] MORDIKE B L.Creep-resistant magnesium alloys[J].Materials Science and Engineering A:Structural Materials Properties Microstructure and Processing,2002,324(1):103-112.
[10] CHEN Z H.Deformation magnesium alloy[M].Beijing:Chemical Industry Press,2005:360-364.
[11] 董婷婷,王渠东,郭炜,等.往复挤压纯镁的组织演变和力学性能[J].材料研究学报,2015,29(8):569-575.
[12] 张曼玉,应韬,曾小勤,等.Mg-Sc二元合金微观组织和力学性能研究[J].铸造技术,2018(5):947-951.
[13] 雷维维,梁伟,黄志军.热挤压后纯镁的组织与力学性能研究[J].热加工工艺,2016,45(23):125-127.