DETERMINATION OF THERMAL STRESS AND ELONGATION ON DIFFERENT CERAMIC COATED Ti-6Al-4V ALLOY AT ELEVATED TEMPERATURES BY FINITE ELEMENT METHOD

Recently, coating applications of hard engineering ceramics on metallic alloys have become notably widespread in order to expand the service life of the critical design components working in though conditions like corrosive/oxidative or erosive/abrasive media. Even though scientific efforts on coating processes and their effects on wear and corrosion performance have been studied for years, there is a lack of investigation about mechanical properties, especially thermo-mechanical features of hard ceramic coated metals. In this paper, on the purpose of determination of the thermal stress distribution, effects of coating materials (Al2O3, AlN and TiB2) and coating thickness (400 mu m, 600 mu m, and 800 mu m) on Von-Mises stress, shear stress and resultant displacement for single and full surface coating models designed on Ti-6Al-4V base material are investigated at 373 K, 573 K and 873 K. The results show that modulus of elasticity and thermal expansion coefficient of coating ceramic materials and base metallic material affect the elongation and stress values observed on designed models significantly. Besides, coating thickness and ambient temperature are also effective on thermal properties. Lastly, it can be pointed out that resultant displacement values on a single-surface coating model are higher than full surface coating model. However, Von-Mises and shear stress values calculated with finite element analysis on single surface coating model is lower than the values read for full-surface coating model.