镁基块体金属玻璃基复合材料研究

Study of Mg-based Bulk Metallic Glass Matrix Composites

在空气中采用普通铜模浇铸法制备了两种成分的Mg-Cu-Al-Y金属玻璃复合材料(Mg65Cu23Al2Y10和Mg65Cu20Al5Y10)试样。XRD分析表明,随着Al的加入,原本的非晶“馒头峰”上出现了晶体增强相的尖锐峰;DSC曲线中晶化放热峰表明两种合金基体为非晶态结构,相比于纯玻璃态时,复合材料的玻璃转变温度和初始晶化温度均下降,过冷液相区变窄,同时表现为多级晶化;尽管两种合金的成分只有细微差别,但微观组织却相差很大,当Al含量为2%时,显微组织中有明显的针状组织存在,而Al含量为5%时,为粒状组织。显微硬度测试表明:当Al含量为2%时,硬度值明显提高,均值达到了276HV,比完全非晶态下的硬度值高出42HV。

Mg-Cu-A1-Y metallic glass matrix composites （Mg65Cu23Al2Y10, Mg65Cu20Al5Y10） were prepared by a method of pouring melted alloy into copper mould in the air. The analyses by XRD show that with the addition of Al, the sharp peaks of reinforced crystal-phases are superimposed on the broad scattering pcaks of amorphous matrix. The crystallization exothermic peaks in DSC graph show that the structure of the matrix is glass-state. Compared with the metallic glass, the glass transition temperature and the onset temperature of primary crystallization of composites reduces, the supercooled liquid region becomes narrow. Although the compositional difference of the alloy is very samll,they show essentially different microstructure. Needle-shape phases of Mg65Cu23Al2Y10 alloy can be observed when the content of A1 is 2%, but grain structure is formed in Mg65Cu20Al5Y10 alloy when the content of Al is 5%. The average microhardness of Mg65Cu23Al2Y10 is 276HV when the content of Al is 2%, which is 42 HV more than the metallic glass.