多组元替换Zr-Al-Ni-Cu-Ag金属玻璃的热稳定性和晶化行为

Thermal Stability and Crystallization Behavior of Zr-Al-Ni-Cu-Ag Metallic Glasses with Multicomponent Replacement

摘要:

为提高金属玻璃的热稳定性并获得大过冷液相区，研究了成分为Zr_65-x(Al_0.21Ni_0.29Cu_0.04Ag_0.46)_35+x（x=0，7.5，15.0，22.5）的金属玻璃，重点分析了组分浓度对合金热稳定性、热诱导沉淀相以及力学性能的影响。结果表明，随着合金组分浓度的增加，非晶漫散射峰的峰位向更高角度偏移，出现了玻璃转变现象。随着玻璃转变温度（T_g）和晶化温度（T_x）增加，液相线温度（T_l）降低，导致T_x和T_g之间的温度差（ΔT_x）减小，约化玻璃转变温度（T_rg）增大。此外，形核激活能（E_x）和长大激活能（E_p1）随着溶质浓度的增加而增加。初晶从四方Zr₂Ni、Zr₂(Cu, Ag)、ZrAg和六方Zr₅Al₃相的组合转变为单一四方ZrAg相，维氏硬度呈现出增加的趋势。通过研究，发现了具有141 K过冷液相区（ΔT_x）和高热稳定性的新型金属玻璃Zr_65-x(Al_0.21Ni_0.29Cu_0.04Ag_0.46)_35+x（x=7.5），且具有较强的抵抗晶化的特性。本研究采用的多组元替换策略对提高金属玻璃的热稳定性具有重要意义。

Abstract:

In order to improve the thermal stability and to obtain a large supercooled liquid region of metal glasses, the Zr_65-x(Al_0.21Ni_0.29Cu_0.04Ag_0.46)_35+x (x=0, 7.5, 15.0, 22.5) metallic glasses were investigated. The effects of component concentrations on the thermal stability, heat-induced precipitate phases, and mechanical properties were analyzed. Results show that with increasing the component concentrations, the peak position of the broad diffraction pattern shifts towards higher angles, indicating the occurrence of glass transition phenomenon. With increasing the glass transition temperature (T_g) and crystallization temperature (T_x), the liquidus temperature (T_l) is decreased, leading to decrease in the temperature difference (namely supercooled liquid region, ΔT_x) between T_x and T_g and resulting in the increase in reduced glass transition range (T_rg). Additionally, the nucleation activation energy (E_x) and the growth activation energy (E_p1) are increased with increasing the solute concentration. The primary crystal changes from the combination of tetragonal Zr₂Ni, Zr₂(Cu, Ag), ZrAg, and hexagonal Zr₅Al₃ phases into the single tetragonal ZrAg phase. The Vickers hardness is also increased with increasing the solute concentration. In this research, a novel metallic glass, Zr_65-x(Al_0.21Ni_0.29-Cu_0.04Ag_0.46)_35+x (x=7.5), is developed, which presents a large ΔT_x of 141 K, high thermal stability, and strong crystallization resistance. This research adopting the multicomponent replacement strategy is of great significance to improve the thermal stability of metallic glasses.