Thermographic characterisation of a laser surface engineered ceramic coating on metal

Laser-material interactions consist of complex, and generally short-lived, but intense events. Hence, many important aspects and effects of these interactions are not directly measurable, such as temperature distributions within the material. In the present study, the effect of temperature distribution on the residual stresses developed during laser surface engineering of ceramic composite coating on metal has been investigated. Infrared thermography technique has been employed as a means to measure the temperature distribution within the substrate while the laser beam is directed at the surface of the coating. Temperature distribution is generally a function of the laser input parameters, such as the laser beam power and the traverse velocity of the beam. Hence, variation in the temperature distribution and the consequent stresses developed within the composite coating due to the changing input parameters have also been investigated. The rapid processing in complement with precise control of the process based on in-situ thermographic measurements provides numerous opportunities for a high power laser as a advanced manufacturing tool.List of symbols Azimuthal angle - Tilt Angle - Q Heat energy - t Time - T Temperature - k Thermal conductivity - Density - C_p Heat capacity - Strain - d Interplanar spacing - Poissons ratio - E Youngs modulus - Stress