High temperature nitriding behavior of Fe-1mass%M (M=Al, Cr, V, Ti) binary alloys

摘要

Nitriding is one of the most important surface hardening treatment processes in practical use, which utilizes precipitation hardening by fine alloy nitrides. Since it is performed usually at relatively low temperature around 823K, long processing time is required to obtain sufficient thickness of nitrided layer. Raising the process temperature is an effective way for reducing the processing time. However coarsening of precipitates and formation of austenite phase on the surface and resultant softening would take place in nitriding at higher temperatures, although such behavior is not clear. This work aims to reveal the effect of the nitriding temperature on hardness and microstructure change during plasma nitriding in various Fe-M binary alloys.