Solutionand Ageing Behavior Of W-30ZRC Composites

In this work, solution and aging behavior of W-30vol% ZrC composites at high temperature has been studied. The effection of solution and ageing treatment process included temperature and time to the W-30ZrC composites phase composition and microstructure has been studied with the methods of XRD, SEM, TEM and Vickers hardness test methods, at the same time, the work of establishing the calibration curves for W and ZrC content. And for the most important, the work of calculation the changing amount of W in ZrC solid solution and the different lattice parameter has been successfully completed.Density test results show that the high temperature solution treatment can effectively promote the densification behavior. As the solution treatment temperature and time, the composite density rise, 2500℃1.5h after solution treatment composite density reached 99.2%; composites after aging treatment did not change the density large, were 99.5%.XRD analysis indicated that, W-30ZrC composite after different solution treatment and aging process, the main phase composition unchanged at W and ZrC two-phase, no new phase formation; by the quantitative XRD analysis results , with the solution treatment temperature and time to extend the solution W in the amount of ZrC increases, which subsequently reduced the relative content of W, ZrC content increased; aging treatment, W as the relative content of aging temperature increased, aging time was extended after first reducing the increasing trend, ZrC and W changes the content of the opposite.ZrC lattice constant of accurate measurement results show that, with the solution temperature and time extension, ZrC solid solution of the lattice constant decreases; as the aging temperature increased, the larger lattice constant, with the aging time, was the first decrease after increasing.Microstructure observation shows that the composite sintered ZrC grains and grain boundaries within the large number of precipitates, diffraction analysis proved to be W precipitates; after solution treatment lead to precipitates disappear, W grains occur within the a large number of dislocations; aging treatment, there was no precipitate, but the W grain interior dislocations disappear. From the results of W-30ZrC composites changing Vickers hardness can be seen, composites hardness with the aging time of the extension of the larger, with the solution treatment temperature increased at first and then decreased, the maximum hardness value reached 7.02 GPa. Aging treatment, the hardness increases with the aging temperature decreases with prolonged aging time larger. Among them, only the lowest hardness value 5.89GPa.