Superior strength and wear resistance of mechanically deformed High-Mn TWIP steel

In the present study, the mechanical and wear behaviour of the surface-mechanically treated high-manganese (high-Mn) twinning-induced plasticity (TWIP) steel were investigated. The TWIP alloy was first designed and fabricated via surface-mechanical attrition treatment (SMAT) system and the mechanical properties including strength, wear behaviour as well as the microstructural evolution were thereafter determined. Transmission electron microscopy (TEM) characterization revealed a typical dislocation as a result of the surface treatment as well as the formation of twin layers with a reduced stacking fault energy (SFE). Due to the ultra-fine grain refinement caused by plastic deformation during surface treatment, a microhardness value of 489 HV can be obtained after treatment. Likewise, the yield strength of the high-Mn TWIP steel could be enhanced from 360 MPa to 813 MPa and a reduction in elongation to failure of about 20 % can be achieved. The wear test showed that the treated TWIP steel possessed a reduced friction coefficient and improved wear resistance at different testing loads, attributed to the nanoscale refinement of grains induced during treatment. The strength, hardness, and wear resistance of the fabricated TWIP alloy improves significantly, thanks to surface treatment by SMAT.