Experimental Study on Residual Stresses of Al_2O_3 Coating by Laser Re-melting

摘要

The surface of Al_2O_3 coating sprayed on 40Cr substrate was re-melted with high power continuous CO_2 laser, and its micro-hardness and residual stresses were measured, respectively. The strengthening mechanism of Al_2O_3 coating by laser re-melting was analyzed and discussed. The experimental results shown that the surface of Al_2O_3 coating by laser re-melting is neat and smooth, and its compositions are even, its structures are compact, and Al_2O_3 coating is evenly distributed in its surface with grain forms, and its micro-hardness increases about 200%; Residual stress of Al_2O_3 coating by laser re-melting is changed into compressive stress from tensile stress, which is benefit to improving bonding strength of coating-substrate interface.