Comparisons of grain size-density trajectory during microwave and conventional sintering of titanium nitride

A broad range of sintering temperatures and hold times had been systematically varied to investigate the relative density/grain size trajectories for titanium nitride specimens during microwave and conventional sintering. Fully dense materials with a submicron grain size (around 170 nm using microwave sintering and around 240 nm using conventional sintering) are achievable using the simple ramp & hold approach. Improvement of the mechanical properties, including increase in hardness (from 18 to 20 GPa), fracture toughness (from 2.9 to 3.4 MPa m(1/2)), was observed due to grain refinement in case of microwave sintering. The area for the future optimization for the sintering schedule for further grain refinement has been proposed. (C) 2013 Elsevier B. V. All rights reserved.