Influencing effects of variant laser pulse energy on fatigue behavior induced via LSP

The set objective in this current study is to understand the effects of laser shock processing of variant laser pulse energies on residual compressive stress, microhardness, fatigue fracture, and fatigue life on the application of aircraft lug material. The effect of three variant laser pulse energies 3, 4, and 5.7 J were employed to examine alongside the laser processing parameters. A Q-switch (Nd-YAG) laser system was used in this experiment with wavelength, pulse width, spot diameter, and overlapping ratios of 1046 nm, 10 nm, 3 mm, and 50 %, respectively. After LSP, the superficial layer stress state shows varied results from tensile to residual stress of 50 MPa, to −225 MPa, −260 MPa, and −301 MPa, after 3 J, 4 J, and 5.7 J, respectively. The microhardness for the as-received specimen was 137 HV. However, after LSP it increased to 198 HV, 210 HV, and 223 HV, respectively. The fatigue life performance also experienced a significant increase up to 53,371 (2 x 105 cycles).