Anti-perovskite carbides and nitrides A3BX: A new family of damage tolerant ceramics

Synergy effect of high stiffness and good damage tolerance is always the focus of the development of novel structural materials. Herein, a new strategy on the future damage tolerant material design is proposed to merge the strong covalent bonds into the easy shear deformed A3B metallic box. This goal is realized by studying 126 A3BX phases and establishing a database on their mechanical properties through high-throughput first principles calculations. The combination strategies of A3B metallic box and XA3 octahedra show intensive influences on the expected mechanical properties. The family includes 49 quasi-ductile compounds. Among them, four compounds (Ti3AlN, Mn3CuN, Ti3TlN and Ni3SnN) exhibit excellent damage tolerance and the other six compounds (Mn3NiN, Mn3GaC, Mn3GaN, Mn3SnC, Cr3SnN, Co3AlC) show both damage tolerance and high stiffness. Their competitive high temperature properties are demonstrated through the detailed investigation on the typical cases of Co3AlC and Ti3TlN. This study leads a novel direction for the design of the future quasi-ductile and high stiffness ceramics.