Effect of autocatalysis on variant selection of α precipitates during phase transformation in Ti-6Al-4V alloy
Effect of autocatalysis on variant selection of α precipitates during phase transformation in Ti-6Al-4V alloy
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DOI：
10.1016/j.commatsci.2016.07.032
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发表时间：
2016-11
影响因子：
3.3
通讯作者：
Di Qiu;P. Zhao;Rongpei Shi;Yunzhi Wang;Wei-jie Lu
中科院分区：
文献类型：
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作者：
Di Qiu;P. Zhao;Rongpei Shi;Yunzhi Wang;Wei-jie Lu
研究了α相之间的弹性相互作用及其对变体选择的影响。首先用相场微弹性理论计算了半共格α板条周围的应力场，然后用三维相场模型模拟了Ti-6Al-4V中β→ α+ β的析出过程。从相场模拟中获得的初级（预先存在的）α变体诱导的次级α变体的取向与实验中通常观察到的α团簇中的变体的取向一致。实验中常见的[1 1 2 <$0] α/60°、[10 1 5 5 3] α/63.26°和[0 0 0 1] α/10.53 °等α/α取向关系的形成可能是α变体成核和生长过程中自催化作用的直接结果。此外，在初生α板条周围同时形核的α变体之间对有限数量的优先形核位置的竞争也导致选择相对于初生α沉淀物具有特定晶体学取向的变体。
The elastic interactions among α precipitates and their effects on variant selection are investigated. The stress field around a semi-coherent α lath is first calculated using phase field microelasticity theory and then the precipitation process of β→ α+ β in Ti-6Al-4V is simulated using a 3-D phase field model. The orientations of secondary α variants induced by a primary (pre-existing) α variant obtained from the phase field simulations are consistent with those of variants within commonly observed α clusters in experiments. The formation of α/α orientation relationship of the [1 1 2¯ 0] α/60°-type,[10‾ 5 5 3] α/63.26°-type and [0 0 0 1] α/10.53°-type frequently observed in experiments could be a direct consequence of autocatalysis during nucleation and growth of α variants. Moreover, the competition among α variants nucleated simultaneously around a primary α lath for limited number of preferred nucleation sites also results in the selection of variants possessing specific crystallographic orientation with respect to the primary α precipitates.