Zn对Mg基金属玻璃形成能力及晶化行为的影响

Effects of Zn on Glass-forming Ability and Crystallization Behavior of Mg-based Metallic Glass

在空气中采用普通铜模浇铸法制备Mg65Cu25-xZnxY10(x=3,5,7)块体合金试样,研究Zn含量对Mg65Cu25-xZnxY10(x=3,5,7)非晶合金的形成能力、晶化行为的影响。用X射线衍射确定合金的结构组成,差示扫描量热计(DSC)分析合金的玻璃转变、晶化和熔化行为。结果表明,当x=5时,合金的非晶形成能力最强,采用楔形铜模浇注完全非晶态厚度最大可达3mm,同时玻璃转变温度和初始晶化温度最低,但约化玻璃转变温度Trg最大,为0.581。而当x=3时,合金的过冷液相区最宽,ΔTx为63.8K。与其他合金相比,Mg65Cu20Zn5Y10四元合金的晶化转变更为复杂,表现为明显的四级晶化。

Mg65Cu25-xZnxY10（ x = 3, 5, 7） bulk metallic glasses are prepared by a method of melt casting into copper mould in the ambient atmosphere, and the effects of Zn on the glass-forming ability and crystallization behavior of the alloys are studied. The structures of as-cast alloys are analyzed with X-ray diffraction, and the glass transition, crystallization and melting behavior of the alloys are investigated by using differential scanning calorimetry（DSC）. With the x = 5, glass-forming ability of the alloy is the best, metallic glass strip with 3 mm thickness can be obtained by the copper wedge mould cast, at the same time, the glass transition temperature and the onset temperature of primary crystallization are the lowest, but the Trg is the greatest, about 0. 581. For x = 3, the alloy has the largest supercooled liquid region, about 63.8K. Compared with other glass, the quaternary Mg65Cu20Zn5Y10 glass exhibits a more complex crystallization process performed through four steps.