脉冲磁场对石墨型铸造Mg-6Gd-3Y-0.6Zr合金组织及性能的影响

Effects of Pulse Magnetic Field on Solidification Structure and Mechanical Properties of Mg-6Gd-3Y-0.6Zr Alloy Cast in Graphite Mold

利用金相显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)及拉伸试验机等手段,研究了脉冲磁场对石墨型铸造Mg-6Gd-3Y-0.6Zr合金凝固组织及力学性能的影响。结果表明,脉冲磁场处理可有效细化合金晶粒并提高其力学性能。与未处理的合金相比,当脉冲电压为300 V、脉冲频率为5 Hz、模具预热温度为400℃时,合金晶粒尺寸减小了32.9%,其抗拉强度和伸长率分别提高了14.1%和16.2%。在200~600℃内,随着模具预热温度升高,合金的晶粒尺寸逐渐增大;在0~300 V内,随着脉冲电压提高,合金晶粒尺寸逐渐减小;在0~10 Hz内,随着脉冲频率提高,合金晶粒尺寸先减小后增加,转折点为5 Hz。该合金的力学性能与晶粒尺寸基本对应,合金的晶粒尺寸越小,其力学性能越好。

Effects of pulse magnetic field on solidification microstructure and mechanical properties of Mg-6Gd-3Y0.6Zr alloy cast in graphite mold were investigated by OM,SEM,EDS,XRD and tensile testing machine.The results show that pulse magnetic field treatment can refine grain size of the alloy and improve mechanical properties effectively.With the pulse voltage of 300 V,the pulse frequency of 5 Hz and the die preheating temperature of 400℃,the grain size of the alloy is reduced by 32.9%,and the tensile strength and elongation of the alloy are increased by 14.1%and 16.2%,respectively.In the range of 200~600℃,grain size of the alloy is increased with the increase of die preheating temperature.In the range of 0~300 V,grain size of the alloy is decreased with the increase of pulse volt⁃age.In the range of 0~10 Hz,the grain size of the alloy is decreased at first and then increased with the increase of pulse frequency,and the turning point is 5 Hz.The mechanical properties of the alloy is corresponded to the grain size of the alloy.With the decrease of grain size in the alloy,the mechanical properties are improved.