Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7880462 | Acta Materialia | 2015 | 14 Pages |
Abstract
Through three-dimensional phase-field simulations, dislocations are found to exert significant influences on variant selection and subsequent development of transformation texture during α precipitation in α/β titanium alloys. It is found that, for the dislocation configurations considered in the current study, the elastic interaction between α precipitates and dislocations dominates variant selection during the nucleation stage, whereas the habit plane orientations of α precipitates relative to the dislocation lines play an important role in variant selection during the growth stage. In general, edge dislocations exhibit a much more prominent effect than screw dislocations. Various morphological patterns of α precipitates formed by heterogeneous nucleation around dislocations of different configurations are revealed, including clusters of multiple variants and a special “tent” structure that appears as a pyramid with each of its faces composed of a particular α variant. Two types of frequently observed clusters of α variants are found to share either a common <1 1 1>β axis or a common {1 1 0}β plane. The primary tent structure is able to induce the nucleation of secondary α through autocatalysis, reducing the degree of variant selection. The effect of undercooling on variant selection is also investigated in the context of competition between the chemical driving force for α precipitation and the elastic interaction between dislocation and precipitate.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
D. Qiu, R. Shi, D. Zhang, W. Lu, Y. Wang,