Selective laser sintering of polymer-coated Al_2O_3/ZrO_2/TiC ceramic powder

摘要

A type of polymer-coated Al_2O_3/ZrO_2/TiC C ceramic powder was prepared. The laser sintering mechanism of polymer-coated Al_2O_3/ZrO_2/TiC powder was investigated by studying the dynamic laser sintering process. It is found that the mechanism is viscous flow when the sintering temperature is between 80 deg C and 120 deg C , and it is melting/solidification when the temperature is above 120 deg C. The process parameters of selective laser sintering were optimized by using ortho-design method. The results show that the optimal parameters include laser power of 14 W, scanning velocity of 1 400 mm/s, preheating temperature of 50 deg C and powder depth of 0. 15 mm. A two-step post-treatment process is adopted to improve the mechanical properties of laser sintered part, which includes polymer debinding and high temperature sintering. After vacuum sintering for 2 h at 1 650 deg C , the bending strength and fracture toughness of Al_2O_3/ZrO_2/TiC ceramic part reach 358 MPa and 6. 9 MPa centre dot m~(1/2) , respectively.