Unusual softening behavior of yield strength in niobium at high pressures
Jing Qiu-Min, He Qiang, Zhang Yi, Li Shou-Rui, Liu Lei, Hou Qi-Yue, Geng Hua-Yun, Bi Yan, Yu Yu-Ying, Wu Qiang
       

X-ray diffraction patterns of a niobium powder sample at 18, 35, 46, and 61 GPa on MAR345 image plate.