Anirudh Hari, Kento Katagiri, Wanghui Li, Dorian P Luccioni, Rayen Lin, Sophie E Parsons, Zipeng Xu, Rohit Hari, Tharun Reddy, Ernest W Cubit, Alexis Amouretti, Jon H Eggert, Yuichi Inubushi, Tetsuo Irifune, Sara J Irvine, Ryosuke Kodama, Michel Koenig, Laura Madril, Takeshi Matsuoka, Kohei Miyanishi, Hirotaka Nakamura, Norimasa Nishiyama, Takuo Okuchi, Masato Ota, Toshimori Sekine, Yusuke Seto, Toru Shinmei, Keiichi Sueda, Yoshinori Tange, Sota Takagi, Tadashi Togashi, Yuhei Umeda, Yifan Wang, Makina Yabashi, Toshinori Yabuuchi, Norimasa Ozaki, Leora E Dresselhaus-Marais
Extreme pressures and temperatures create conditions that allow even hard and brittle materials to flow plastically. Despite extensive research, the limits of flow strength under such conditions remain uncertain, and the mechanisms driving deformation at the relevant stresses are a subject of debate. Using femtosecond in situ x-ray diffraction experiments and large-scale molecular dynamics simulations, we demonstrate that stacking fault-mediated strengthening enables shock-compressed nanopolycrystalline diamond to achieve a peak flow strength of 92 ± 3 GPa at a stress of 212 ± 6 GPa. Our findings show that extreme conditions can unlock ultrahigh strength via a complex array of competing deformation mechanisms and thermodynamic effects.