Dynamic Polymorphism of Some Binary Iron Alloys

Abstract

Investigations of the pressure‐induced polymorphism of the Fe‐V, Fe‐Mo, Fe‐Co, and Fe‐C alloy systems have been carried out by dynamic techniques. The addition of vanadium to iron is found to raise the transition pressure very strongly, to some 575 kbar for 25 wt% vanadium content. The Fe‐Co study indicates that long‐range order does not have an appreciable effect on the transformation. The initial mixed phase state of the Fe‐Mo system is clearly manifested in the transition behavior, generally fulfilling expectations. Variations of the transition parameters by various sample heat treatments are demonstrated in the Fe‐C system investigation. The dynamic transformation parameters for pure iron have been reappraised, and are found to be P_b=129±1 kbar, v/v₀=0.9360±0.0005. A summary of transition pressures for binary iron alloys is provided.