The laser radiation has great important in many applications. In this paper we have studied the influence of laser radiation on solid material. We use a (800 µs) pulsed laser ND: YAG with (1.06 µ m) wave length, (3 J) energy and power density of (7.6 X 106 W/cm2 ) . We have deduced a mathematical function for laser energy with time, then deducing a function for laser power density with time because practically assumed to be constant. A lead material used in this paper for study, we have deduced mathematical functions for thermal properties (conductivity, specific heat, density, diffusivity) with temperature, and solve the partial differential equation (P.D.E) which represent the heat transfer of laser radiation to the material in one dimension, presumes variable and constant laser density ( I=I0 and I=I(t)) , also the thermal properties conductivity , specific heat ,density and diffusivity ( K=K0 and K=K(T),C=C0 and C=C(T), T 0and ( ) ,du=du0 and du=du(T)) respectively . The results reveal that the time of evaporation increase when the laser density is taken as variable with time , also it increase when the thermal properties were vary with temperature . We used (Matlab 7.0) to perform all programs which related with this paper
د.حميد حسام حميد | Hameed Husam Hameed | 5556