氧对Vitreloy 105金属玻璃热稳定性的增强作用

Enhancement of Thermal Stability by Oxygen Impurity for Vitreloy 105 Metallic Glass

通过构建TTT图及先析相析出动力学分析,研究氧对Vitreloy105合金热稳定性及玻璃形成能力(GFA)影响的"全景效应"。结果发现,由于先析相的变化,氧对合金热稳定性及GFA具有不同的影响:在连续冷却结晶过程中,氧致f.c.c.-Zr2Ni作为先析相时,氧降低合金的GFA;但是,在获得玻璃态后的重新加热晶化过程中,b.c.t.-Zr2Ni作为先析相时,氧具有抑制b.c.t.-Zr2Ni析出、提高合金热稳定性的作用。合金先析相的结构取决于结晶或晶化的动力学条件。

A ＇panoramic effect＇ of oxygen impurity on the thermal stability and GFA of Vitreloy 105 metallic glass was investigated based on the construction of TTT diagram and the kinetics analysis of primary phase precipitation. It was found that the oxygen impurity has different influences on the alloy＇s thermal stability and GFA in the content range of 0.015 %-0.045 % （mass） because the primary phase was changed. The oxygen decreases the alloy＇s GFA during continuously cooling crystallization for the oxygen-induced f.c.c.-Zr2Ni precipitates as the primary phase. However, the oxygen retards the precipitation of b.c.t.-Zr2Ni phase and enhances the alloy＇s thermal stability during the reheating recrystallization of glassy alloy for the b.c.t.-Zr2Ni as the initial precipitation phase. The crystal structure of primary phases depends on the conditions for oxygen diffusion during the crystallization above nose temperature, Tn, and the recrystallization below Tn.