Effect of atmospheric-controlled induction-heating fine particle peening on wear resistance and fatigue properties of maraging steel fabricated by laser powder-bed fusion

Maraging steel components fabricated by laser powder-bed fusion, which is a technique of additive manufacturing, are expected to be used widely because of their high strength, hardness and toughness. To apply maraging steel manufactured by laser powder-bed fusion in wider industrial fields and prevent the components from fracture, a study was conducted to improve the wear resistance and fatigue properties of the steel by an atmospheric-controlled induction-heating fine particle peening surface modification technique. The technique developed can create hard intermetallic compound layers and introduce peening effects, which are expected to improve the wear resistance and fatigue properties of maraging steel fabricated by laser powder-bed fusion. The prepared specimens were examined using optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, laser microscopy, X-ray diffraction, micro-Vickers hardness testing, nano-indentation testing, reciprocating ball-on-disk wear tests and axial fatigue tests. It was revealed that atmospheric-controlled induction-heating fine particle peening using mechanically milled particles formed Fe-Al intermetallic compound layers with high hardness, introduced compressive residual stresses and increased the hardness of the maraging steel substrate owing to age hardening. In conclusion, atmospheric-controlled induction-heating fine particle peening can simultaneously improve the wear resistance and fatigue properties of maraging steel fabricated by laser powder-bed fusion within a few minutes. These achievements can expand applications of maraging steel fabricated by laser powder-bed fusion.