A generalized thermoelastic Stefan problem with spatio-temporal nonlocal effect in picosecond pulse laser material processing.

The Stefan conditions are suitable for describing the solid-liquid phase change processes with moving interface. However, the existing literature only focuses on the Stefan problem of heat conduction and does not involve the thermo-mechanical coupling effects. In this work, the generalized thermoelastic Stefan problem with spatio-temporal nonlocal effect is investigated. The solid-liquid phase change of silicon with picosecond pulse laser machining is depicted by the Stefan interface conditions. We find the solutions making use of Laplace transformation and Laplace numerical inverse transformation. The temperature distribution at the moment of surface melting is seen as the initial state of the second phase. The distributions of transient thermoelastic responses under different laser intensities, pulse widths, fractional order parameters, spatial nonlocal parameters and time are obtained and expressed graphically. • The introduction of Stefan conditions into the nonlocal generalized thermoelasticity. • The solid-liquid interfaces moving with time due to laser processing are considered. • The temperature at the surface melting moment is taken as the initial condition. • The heat taken away by vaporization is considered in the boundary condition. • With laser intensity increasing/duration decreasing, the transient responses increase. [ABSTRACT FROM AUTHOR]