机械合金化制备Zr_(50)Cu_(40)Al_(10)非晶合金粉末及其晶化研究

Preparation of Zr_(50)Cu_(40)Al_(10) amorphous powder by mechanical alloying and its crystallization behaviors

以金属Zr、Cu和Al为原料,通过真空熔炼和气体雾化制备Zr-Cu-Al合金粉末,再经高能球磨得到Zr50Cu40Al10非晶合金粉末。采用氮/氧分析仪、X射线衍射仪(XRD)、扫描电镜(SEM)和热分析仪(DSC)对其非晶形成能力及晶化行为进行研究。结果表明,球磨120h后可获得Zr50Cu40Al10非晶合金粉末,且随球磨时间增加,粉末的颗粒尺寸逐渐减小,90h后达到亚微米级。球磨过程中由于铁的增加,使合金的结构"混乱度"增加、负混合热增大,因而热稳定性增强,其过冷区间ΔTx为62K,约为雾化法制备的非晶合金粉末的2倍。此外,采用非等温晶化方法,用KISSINGER方程计算出机械合金化Zr50Cu40Al10非晶合金的玻璃转变和初始晶化的表观激活能分别为152.6kJ/mol和172.4kJ/mol,远小于相应的气体雾化法制备的Zr50Cu40Al10非晶合金粉末表观激活能,其原因是粉末中氧含量和体系自由能较高。

Zr50Cu40Al10 amorphous powder was prepared by mechanical alloying using Zr-Cu-Al alloy powder fabricated by vacuum smelting and gas atomization. The forming and crystallization behaviors of Zr50Cu40Al10 amorphous alloy powders were investigated by X-ray diffractometry （XRD）,content measurements,scanning electron microscopy （SEM） and differential scanning calorimetry （DSC）. The results show that Zr50Cu40Al10 amorphous alloys can be prepared after 120 h ball-milling. The particle sizes reduce and finally reach sub-micron scale with the increasing of milling time. As a result of the increase of iron during the milling process,the structure confusion and the negative mixing heat are increased. Meanwhile the supercooled liquidus region ΔTx is about 62 K,which is about twice as much as that of fabricated by argon gas atomization. The non-isothermal crystallization kinetics of the amorphous powder was investigated by using KISSINGER method. The glass transition and onset crystallization activation energies for the amorphous alloys made by the mechanical alloying are 152.6 kJ/mol and172.4 kJ/mol,respectively,which are much smaller than that of fabricated by argon gas atomization.