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通过合金制备、金相显微镜和扫描电镜等方法研究了稀土元素Y对Mg-Al合金组织细化的影响。结果表明,适量Y的加入能明显细化基体晶粒,使β相分布更为弥散,Y的加入还使基体中出现点状新相Al2Y。冷速为200℃/min时,Mg-5Al和Mg-7Al合金中加入0.5%Y时的组织和成分更均匀,细化效果最好,晶粒直径分别由92.64μm、82.40μm变为52.83μm、39.47μm,β相含量由11.91%、12.17%变为8.29%、8.81%,合金硬度从50.1 HV5和52.8 HV5升高到56.4HV5和62.2 HV5;随着Y含量的进一步增多,合金又开始呈粗化趋势。在同样的冷速和变质条件下,Mg-7Al合金比Mg-5Al合金晶粒更细,变质效果也更好。
The effects of rare earth element Y on the microstructure refinement of Mg-Al alloy were studied by means of alloy preparation, metallographic microscope and scanning electron microscope. The results show that the addition of proper amount of Y can remarkably refine the matrix grains and make the β phase disperse more. The addition of Y also makes the point-like new phase Al2Y appear in the matrix. When the cooling rate is 200 ℃ / min, the microstructure and composition of Mg-5Al and Mg-7Al alloy are more uniform and the refining effect is best when 0.5% Y is added. The grain diameter changes from 92.64μm and 82.40μm to 52.83μm , 39.47μm, the content of β phase changed from 11.91% and 12.17% to 8.29% and 8.81% respectively. The hardness of the alloy increased from 50.1 HV5 and 52.8 HV5 to 56.4HV5 and 62.2 HV5. With the further increase of Y content, Roughening trend. At the same cooling rate and metamorphic conditions, the Mg-7Al alloy is finer than the Mg-5Al alloy and the deterioration effect is better.