Temperature dependence of elastic and plastic deformation behavior of a refractory high-entropy alloy
Temperature dependence of elastic and plastic deformation behavior of a refractory high-entropy alloy
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DOI：
10.1126/sciadv.aaz4748
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发表时间：
2020-09-01
期刊：
影响因子：
13.6
通讯作者：
Liaw, Peter K.
中科院分区：
文献类型：
--
作者：
Lee, Chanho;Kim, George;Liaw, Peter K.
单相固溶耐火高熵合金(HEAs)具有优异的力学性能，如较高的屈服强度和良好的高温软化性能。因此，深入研究体心立方(BCC)耐火材料的变形行为是探索其变形机制的关键。采用实验和理论计算相结合的方法，研究了单一体心立方NbTaTiV耐火材料HEA的高温弹塑性变形行为。原位中子衍射结果显示了随温度变化的弹性各向异性变形行为。用原位中子衍射法测定了单晶弹性模数、宏观杨氏模数、剪切模数和体弹性模数，与第一性原理计算、机器学习和共振超声波谱结果符合得很好。此外，利用Williamson-Hall曲线模型和大角度环形暗场扫描电子显微镜定量描述了不同于传统体心立方合金的刃位错主导塑性变形行为。
Single-phase solid-solution refractory high-entropy alloys (HEAs) show remarkable mechanical properties, such as their high yield strength and substantial softening resistance at elevated temperatures. Hence, the in-depth study of the deformation behavior for body-centered cubic (BCC) refractory HEAs is a critical issue to explore the uncovered/unique deformation mechanisms. We have investigated the elastic and plastic deformation behaviors of a single BCC NbTaTiV refractory HEA at elevated temperatures using integrated experimental efforts and theoretical calculations. The in situ neutron diffraction results reveal a temperature-dependent elastic anisotropic deformation behavior. The single-crystal elastic moduli and macroscopic Young's, shear, and bulk moduli were determined from the in situ neutron diffraction, showing great agreement with first-principles calculations, machine learning, and resonant ultrasound spectroscopy results. Furthermore, the edge dislocation-dominant plastic deformation behaviors, which are different from conventional BCC alloys, were quantitatively described by the Williamson-Hall plot profile modeling and high-angle annular dark-field scanning transmission electron microscopy.