Nanostructuring and Hardening of Subsurface Layers in Structural Steels by Laser Heat Treatment Followed by High-Frequency Mechanical Impact Treatment: Effects of Carbon Content and Alloying Scheme

The laser heat (LH) treatment followed by high-frequency mechanical impact (HFMI) treatment effects on the structure and hardness of the gradient-hardened near-surface layers of the carbon and tool steels are studied in this work. The gradient structure is formed in the near-surface layers in the AISI 1045, AISI O2, and AISI D2 steels after the combination of the laser surface transformation hardening followed by the multi-pin ultrasonic impact peening. The multi-pin HFMI treatment provided the nanostructured surfaces hardened by the scan-based LH treatment. The nanostructured steels on the surface with significantly reduced roughness and increased hardness, which can be effective in terms of desired increase in wear and anti-corrosion resistance.