Strengthened by Oxygen doping, the single-phase body-center-cubic (BCC) TiZrHfNbO refractory high-entropy alloys (HEAs) become strong and ductile. However, phase stability at intermediate temperature and the effects of Oxygen addition on the deformation behavior during tensile tests need to be well understood. In the present work, the phase decomposition of (TiZrHfNb)_100-xO_x HEAs with Oxygen doping in the range of x = 0, 0.5, 1, 1.5, 2 was examined at 873 K. The formation of hexagonal-close-packed (HCP) solid-solution precipitates in submicron size, enriched with Hf, Zr and O elements, were investigated by a combination of X-ray diffraction, transmission electron microscopy and atom probe tomography. Tensile tests of alloys annealed at both 1273 and 873 K were conducted. It was found that doping Oxygen increased the yield strength and maintained ductility for alloys annealed at 1273 K, while formation of HCP precipitates after annealed at 873 K deteriorates the plasticity significantly. To unveil the deformation behaviors, in situ synchrotron X-ray diffraction experiments were applied in the current research. The single-crystal elastic constants and shear elastic anisotropy of HEAs with and without Oxygen doping were calculated and found similar to those of “Gum Metal” Ti alloy. Yet current HEAs possess higher BCC phase stability than “Gum Metal”, and no stress-induced phase transformation was detected during deformation.

通过氧掺杂的增强，单相体心立方（BCC）TiZrHfNbO难熔高熵合金（HEA）变得坚固而易延展。然而，需要很好地理解在中间温度下的相稳定性以及在拉伸试验中添加氧气对变形行为的影响。（TiZrHfNb）_100-x O _x的相分解在873 K下检查了x = 0、0.5、1、1.5、2范围内的氧掺杂HEA。形成了亚微米尺寸的六方密堆积（HCP）固溶体沉淀物，富含Hf，Zr和通过X射线衍射，透射电子显微镜和原子探针层析成像技术对O元素进行了研究。对在1273和873 K退火的合金进行了拉伸试验。发现掺杂氧增加了在1273 K退火的合金的屈服强度并保持了延展性，而在873 K退火后的HCP析出物的形成显着降低了可塑性。为了揭示变形行为，原位同步加速器X射线衍射实验已应用于当前研究。计算了掺和不掺氧的HEAs的单晶弹性常数和剪切弹性各向异性，发现与“口香糖” Ti合金相似。然而，目前的HEA具有比“口香糖金属”更高的BCC相稳定性，并且在变形过程中未检测到应力引起的相变。