Papers by Keyword: Grain Growth Rate

Abstract: Comparison of grain growth of fine-grained and coarse-grained austenite in a Nb-V-Ti microalloyed steel during reheating or equalization at the same temperature was investigated using cold-charging and hot-charging specimens respectively in this study. The results show that the different grain growth behavior appears in fine-grained and coarse-grained austenite. The uniform grain growth and lower growth rate at reheating temperature studied was found in fine-grained austenite, while partial grain growth and higher growth rate was present in coarse-grained austenite. During reheating or equalization, the slow growth rate in fine-grained austenite may be contributed to stronger pinning force of fine precipitates while higher grain growth rate in coarse-grained austenite were believed to the result of lager size difference among part of grains. Grain coarsening occurs in fine-grained austenite as result of precipitate unpinning at extending holding time, but coarse-grained austenite remained wide size distribution at the same condition and this should not be considered as grain coarsening. coarse-grained austenite remained wide size distribution at the

Abstract: In this study, aliovalent ions of Nb2O5 and CoO were co-doped in SnO2 with different Nb2O5/CoO ratios and the grain growth rate of SnO2 was examined. The maximum grain growth rate was observed to be around Nb2O5/CoO = 0.25. Here, the results will be discussed in connection with the defect concentration and the change in diffusion rate-determining species with different Nb2O5/CoO ratios.