Thermal-Mechanical Coupling in Plasma-Sprayed Hydroxyapatite Coating on Ti-6Al-4V Substrate

After considering the interactions of the temperature and deformation during plasma spraying, the classical Fourier transient heat conduction equation was modified, and the thermal elastic-plastic nonlinear constitutive equation, suitable for high temperature and high strain rate conditions, was employed. Thus, a thermal-mechanical coupling model was developed according to the special case of plasma-sprayed hydroxyapatite coating on Ti-6Al-4V substrate. Based on the above coupling model, the temperature field and residual stress field were coupling solved by the finite element method. The effect of substrate preheating temperature on residual stress components was also simulated. Moreover, the material removal method was used to evaluate the residual stress of coating near the interface to get a quantitative comparison. The results show that, the calculated result is consistent with the experimental result; obvious stress concentration appears near the interface edge; it is helpful to reduce the residual stress by increasing properly the substrate preheating temperature.