Laser nitriding of the surface of phosphor bronze

Phosphorous bronze finds applications in industry because of its resistance to fatigue and ease of heat dissipation due to its high thermal conductivity. Laser treatment of bronze surface improves the hardness of the surface through forming a dense layer in the surface region. Consequently, in the present study, laser treatment of a bronze surface is investigated. Thermal stress and temperature fields developed during the laser-treated region are modeled after considering the transient three-dimensional situation in line with the experimental conditions. An experiment is carried out, and the resulting surfaces treated by a laser beam are characterized using scanning electron microscope, energy dispersive spectroscopy, and X-ray diffraction. It is found that high rate of strain developed in the heated region, due to fast-cooling rates, results in high von Mises stress in the surface region. The laser-treated region is free from cracks, and surface hardness increases almost four times above the base material hardness after the laser treatment process.