Synergistic control of plastic instability behavior by multi-heterogeneous austenite morphologies and stacking fault networks in 3Mn steel

Abstract

A multi-heterogeneous austenite morphologies consisting of equiaxed + coarse lath-like + fine lamellar austenite grains is constructed in 3Mn steel through warm rolling in the dual-phase region and tempering. Lower tempering temperature induces a more uniform distribution of multi-heterogeneous austenite morphologies and effectively preserves the stacking fault network formed during warm rolling, which catches exceptional mechanical properties (ultimate tensile strength of 1591 MPa and total elongation of 24.5 %) as well as suppresses plastic instability behaviors including yield plateau and stress serrations in 3Mn steel.