纳米ZrO_(2)颗粒增强Mg-6Zn合金复合材料组织及性能

Microstructure and Properties of Mg-6Zn Alloy Reinforced by Nano-ZrO_(2) Particle

采用搅拌铸造法制备了纳米ZrO_(2)增强的Mg-6Zn合金。利用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)和维氏硬度仪对xwt.%ZrO_(2)/Mg-6Zn(x=0,1,3,5)复合材料的微观组织及性能进行了表征分析。结果表明,纳米ZrO_(2)颗粒加入到镁熔体中未观察到明显的反应产物,其稳定存在于Mg基体中;大量的纳米ZrO_(2)颗粒主要分布在晶界处,并且随着ZrO_(2)含量的增加团聚愈加明显。与Mg-6Zn基体合金相比,随着添加纳米ZrO_(2)含量的增加,复合材料的晶粒尺寸呈现先减小后增大的现象,相应的复合材料的硬度值同样也呈现先增大后减小的现象。当纳米ZrO_(2)的添加量为1wt.%,复合材料展现出了较为均匀的组织和良好的力学性能,其硬度值为HV52.09,较基体合金提高了14.2%。

Nano-ZrO_(2) reinforced Mg-6Zn alloy was prepared by stir casting method.The microstructure and properties of xwt.%ZrO_(2)/Mg-6Zn(x=0,1,3,5)composites were characterized by optical microscope(OM),scanning electron microscope(SEM),X-ray diffractometer(XRD)and Vickers hardness tester.The results showed that no obvious reaction products were observed when nano-ZrO_(2) particles were added to the magnesium melt,which stably existed in the Mg matrix.A large number of the nano-sized ZrO_(2) particles were mainly distributed at grain boundaries,and the agglomeration become more obvious with the increase of ZrO_(2) content.Compared with the Mg-6Zn matrix alloy,with the increase of the nano-ZrO_(2) content,the grain size of the composites decreased at first and then increased,and the hardness value of the corresponding composites also increased at first and then decreased.When the addition amount of the nano-ZrO_(2) was 1wt.%,the composite exhibited relatively uniform microstructure and good mechanical properties.The hardness value of the composite was HV52.09,which was 14.2%higher than that of the matrix alloy.