Improving the high-cycle fatigue properties of twinning-induced plasticity steel by a novel surface treatment process

摘要

A novel method named as surface spinning strengthening (3S) is proposed to achieve gradient microstructures in the surface layer of a high-Mn twinning induced plasticity (TWIP) steel. A hardened layer with depth larger than 1 mm is found in the 3Sed sample, accompanied by a gradient grain-size transition from similar to 300 nm to similar to 50 mu m. In comparison with the as-received sample, the high-cycle fatigue property of the graded sample is enhanced mainly by suppressing the initiation of fatigue cracks, which has its origin from the structure and strength gradient.