Mapping distributions of mechanical properties and formation ability on the ternary B-C-N phase diagram

摘要

Based on first-principles calculations, we present the distributions of mechanical properties and formation ability of amorphous B_xC_yN_z solids on the ternary B-C-N phase diagram. Along the C-BN isoelectronic line, the formation energy shows symmetric distributions; the Young's modulus and ratio of bulk modulus and shear modulus (B/G) show zonal distributions. Amazingly, for some peculiar compositions (B: 13-17 at.%; C: 48-52 at.%; N: 33-35 at.%), B-C-N solids exhibit certain ductile characteristic that is comparable to metals. On the phase area (B: 15-30 at.%; C: 50-60 at.%; N: 20-30 at.%), B-C-N solids possess both excellent hardness and good formation ability. These theoretical results provide valuable guidance for intentionally synthesizing B_xC_yN_z materials with desirable mechanical properties.