Wear Conditions-Dependent Tribological Behavior in Q&P Medium-Mn Steels: The Role of TRIP Effect and Strain Hardening

The microstructural evolution during deformation affects the mechanical properties of materials. Studying the response of wear resistance in multiphase steel containing austenite under different wear conditions is important because of the unclear synergetic evolution of multiphase and varied transformation-induced plasticity (TRIP) effect. In this study, 5Mn steel treated with different quenching and partitioning processes was investigated using high- and low-stress three-body (G65) abrasion wear tests. The results were compared with those for single-phase martensitic steel. In the G65 abrasion wear test, the martensitic steel exhibited the best wear resistance, whereas, in the high-stress abrasive wear, the best wear resistance was obtained for the QP-240 steel containing 9.8 pct retained austenite with low hardness. This indicated a substantial improvement compared to that of martensitic steel. The superior high-stress abrasion resistance of the QP-240 steel can be attributed to the combination of hard martensite and ductile phases (austenite and tempered martensite) as well as a sufficiently enhanced TRIP effect. The subsurface microstructural evolution under two different wear conditions is critical for differentiating the wear properties.