Experimental Investigation of Multiple Laser Shock Peening on Mechanical Properties of Laser Sintering Additively Manufactured Maraging Steel

In this study, the effect of multiple laser shock peening on residual stress, microhardness and tensile properties of direct metal laser sintered Maraging steel 300 is investigated. Multiple laser peening has introduced significant compressive stress in the as-fabricated (−598 MPa) and aged (−653 MPa) samples when compared to the unpeened samples (as-fabricated −270 MPa, aged −310 MPa). Further, it is observed that multiple laser peening led to grain refinement and generation of strain near the surface of laser peened samples. A reduction in crystallite size is observed on increasing the number of laser impacts. The yield strength of laser peened samples is improved by 12.88% and 9.77% in the as-fabricated and aged samples, respectively, in comparison to the unpeened condition. Similarly, the laser peening of as-fabricated and aged samples led to an increase in microhardness by 6.5% and 13.2%, respectively, compared to the unpeened samples.