Effects of phosphorous addition on mechanical properties and retained austenite stability of 0.15C−1.5Mn−1.5Al TRIP-aided cold rolled steels

The effects of a P addition on the mechanical properties and austenite stability are investigated for 0.15C−1.5Mn−1.5Al TRIP-aided cold-rolled steels containing 0.05 and 0.1 wt.% of P. The strength and retained austenite fraction are increased by an increment of the P content. The strengthening of P-added TRIP-aided steel partially comes from the solid-solution hardening effect of P, and a higher fraction of strain-induced martensite plays an important role as well. The elongation of steel containing 0.1 wt.% P is diminished compared with that containing 0.05 wt.% P. This is attributed to the lower mechanical stability of retained austenite in TRIP-aided steel containing 0.1 wt.% of P, which inhibits persistent work hardening during deformation.