Sn的添加对Mg-Cu-Y块体金属玻璃形成能力的影响

Effect of Sn Substitution on Glass Forming Ability of Mg-Cu-Y Bulk Metallic Glasses

通过熔体铜模浇注方法制备了Mg65Cu25-xSnxY10(x=2,4,6)合金,并对它们的玻璃形成能力及晶化行为进行了研究。利用X射线衍射确定合金的非晶态性质,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:在Mg65Cu25-xSnxY10合金体系中,当x=2时,合金的玻璃形成能力最强,能形成的完全玻璃态试样的最大尺寸为3.2mm,其过冷液相区ΔTx和约化玻璃转变温度Trg分别为57.6和0.586。同时合金的熔化曲线表现为单一吸热峰。随着Sn含量的增加,非晶合金的玻璃转变温度Tg及初始晶化温度Txl均呈现下降趋势,同时合金的玻璃形成能力逐渐下降。当x=4和6时,合金的晶化行为表现为明显的多级晶化。

Mg65Cu25-xSnxY10（x=2,4,6） bulk metallic glasses were prepared by a method of melt casting into copper mould in the air and then the effect of Sn on the crystallization behavior and the glassforming ability of these alloys were studied. The structures of as-cast alloys were analyzed with X-ray diffraction. The glass transition, crystallization and melting behavior of the alloys were investigated using differential scanning calorimetry （DSC）. It is indicated that the critical size of glass-forming ability of Mg65 Cu23Sn2Y10 alloy is 3.2mm, and the supercooled liquid region △Tx is about 57.6 while the reduced glass transition temperature Trg is 0.586. The melting exhibits a relatively single endothermie peak. With the increasing x value, the metallic glasses exhibit a reducfon of both the glass transition temperature Tg and the onset temperature of the first crystallization event Txl The glass-forming ability also decrease. When x=4 and 6, the melting exhibits more complex crystallization process performed through three steps.