Al0.5Nb1.5TiV2Zr0.5 难熔高熵合金组织和力学性能

Microstructure and Mechanical Properties of Al0.5Nb1.5TiV2-Zr0.5 Refractory High Entropy Alloy

摘要:

采用真空电弧熔炼制备了Al_0.5Nb_1.5TiV₂Zr_0.5高熵合金，并研究了其微观组织、密度及力学性能。结果表明，Al_0.5Nb_1.5TiV₂Zr_0.5合金由为90.6%（体积分数）的体心立方相和9.4%（体积分数）的C14-Laves第二相组成。合金基体相富含Ti和V，第二相富含Al和Zr。合金的密度为6284 kg/m³，维氏硬度为5197.9 MPa。合金的屈服强度随温度升高而降低，由室温下1082.9 MPa降低到1073 K下的645.0 MPa。压缩应变由室温下的27.20%降低到873 K下的14.94%，这与合金中原子间的相互作用力随温度升高而降低有关。在1073 K时合金应变超过50%，表现出良好的塑性而未发生断裂。压缩测试结果表明，合金韧脆转变温度在873~1073 K之间。

Abstract:

The Al_0.5Nb_1.5TiV₂Zr_0.5 high entropy alloy was prepared by vacuum arc melting, and its microstructure, density, and mechanical properties were investigated. Results show that Al_0.5Nb_1.5TiV₂Zr_0.5 alloy consists of 90.6vol% body-centered cubic phase and 9.4vol% C14-Laves secondary phase. The matrix phase of the alloy is rich in Ti and V, and the secondary phase is rich in Al and Zr. The alloy has a low density of 6284 kg/m³ and Vickers hardness of 5197.9 MPa. The yield strength of alloy is decreased with increasing the temperature: it decreases from 1082.9 MPa at room temperature to 645.0 MPa at 1073 K. The compressive strain decreases from 27.20% at room temperature to 14.94% at 873 K, which is related to the decrease in atomic interaction force when the temperature rises. At 1073 K, the compressive strain of alloy exceeds 50%, indicating the good plasticity without fracture. The results of compression tests show that the ductile-brittle transition temperature ranges from 873 K to 1073 K.