Fast determination of thermal conductivity of aluminum alloy by laser-induced breakdown spectroscopy

Abstract The matrix thermal properties are closely linked to laser-induced plasma, because it is the heat effect predominantly governs the process when the nanosecond-pulsed laser acting on the material, particularly in metallic materials. In the study using a series of pure metal samples, We detected a substantial inverse linear relationship linking the matrix’s thermal storage coefficient of the material to the temperature of the plasma. This discovery reveals that metals exhibiting reduced thermal conductivity or lower specific heat capacity necessitate a smaller amount of laser energy to achieve thermal spreading and to facilitate the transitions to the melted and vaporized states, which consequently results in a higher rate of material removal and higher plasma temperatures. Based on this correlation, a prediction model for the thermal conductivity of aluminum alloys has been developed, employing LIBS technique as analysis method, alongside PLS regression, with a relative error of below 1.5%. It presents a pioneering technique for the swift evaluation of thermal conductivity in aluminum alloys.