冷轧及再结晶退火对TiNbHf难熔中熵合金力学性能的影响

Effect of cold rolling and recrystallization annealing on mechanical properties of TiNbHf refractory medium-entropy alloy

利用真空电弧熔炼炉制备了TiNbHf难熔中熵合金,采用X射线衍射(XRD)、扫描电镜(SEM)、电子背散射衍射(EBSD)和拉伸实验等方法研究了TiNbHf合金的显微组织及力学性能。结果表明:TiNbHf合金的铸态组织为单相BCC结构,经冷轧及再结晶退火处理后仍保持单相BCC结构;合金的晶粒尺寸随着退火温度的升高而增大,屈服强度逐渐降低;在900℃退火0.5 h后,合金发生完全再结晶,强塑性综合表现最佳,其屈服强度和均匀伸长率达638 MPa和19.2%。

TiNbHf refractory medium-entropy alloy(RMEA) was prepared by vacuum arc melting furnace. Microstructure and mechanical properties of the TiNbHf alloy were studied by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), electron backscatter diffraction(EBSD) technique and tensile test. The results show that the microstructure of the as cast TiNbHf alloy is single-phase body-centered cubic(BCC) structure, which can be remained after cold rolling and recrystallization annealing. The grain size of the alloy increases with the increase of annealing temperature, and the yield strength decreases gradually. After annealing at 900 ℃ for 0.5 h, the alloy is completely recrystallized, the comprehensive performance of strength and plasticity is the best, and the yield strength and uniform elongation are 638 MPa and 19.2% respectively.