Sintering kinetics study of mechanically alloyed nanocrystalline Mo–30 wt.% W

The paper details the results of sintering kinetics studies conducted on nanocrystalline Mo–30 wt.% W alloy powders prepared through mechanical alloying route. Both, constant rate of heating method as well as Stepwise Isothermal Dilatometry (SID) technique were used for studying the sintering kinetics. Measured step isothermal shrinkage data were analyzed by Mekipritti-Meng method. The shrinkage data was found to fit well with the rate equation proposed in this method and its validity was established for mechanically alloyed systems. Kinetic parameters were evaluated and sintering was found to occur through two major mechanisms operative successively, which are grain boundary diffusion and lattice diffusion with corresponding energies of activation as 230 kJ/mol and 480 kJ/mol, respectively. The results have been well supported by micro structural evaluation of specimens at different stages of sintering.