Origin of morphological variation of grain boundary precipitates in titanium alloys
Origin of morphological variation of grain boundary precipitates in titanium alloys
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钛合金晶界析出物形貌变化的根源
DOI：
10.1016/j.scriptamat.2022.114651
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发表时间：
2022
影响因子：
6
通讯作者：
Zheng, Yufeng
中科院分区：
文献类型：
--
作者：
Shi, Rongpei;Li, Dian;Antonov, Stoichko;Liu, Xingjun;Zheng, Yufeng
采用三维相场模拟、三维实验表征和晶体取向分析相结合的方法，系统地研究了α钛合金中β析出相的晶界(GB)异形体和魏氏体侧板(WS)的形态变化。发现GBθ的习惯面与宿主GB面之间的倾角α决定了GB析出物的形态。首次观察到由两个临界角(αc1，θ≤θc2)隔开的θgB的三种不同的形态：θc1，GBθ≤θ单独修饰GB作为一个连续的层；αc1和lt；αc2，θ沉淀出现为GBθ≤θ和从它发出的WS的混合物；α>；αc2，WS单独从裸露的θGBs中生长。这种戏剧性的形态变化归因于沿GBP的扩散和GB沉淀的晶内生长之间的动态相互作用及其对θ的依赖。
Morphological variations of grain boundary (GB) allotriomorphs and widmanstatten sideplates (WS) of α precipitate in a β titanium alloy, have been systematically investigated by combining three-dimensional (3D) phase-field simulations, 3D experimental characterization and crystallographic orientation analysis. The inclination angle, θ, between the habit plane of the GB α and the hosting GB plane is found to dictate the morphologies of GB precipitates. For the first time, three distinct regimes of α morphology at a β GB, separated by two critical angles (θ c 1, θ c 2) are observed: θ≤ θ c 1, GB α alone decorates the GB as a continuous layer; θ c 1< θ≤ θ c 2, α precipitate appears as a mixture of GB α and a WS emanating from it; θ> θ c 2, WS alone grows directly from bare β GBs. The dramatic morphological variation owes its origin to the dynamic interplay between the spreading along GBP and the intragranular growth of the GB precipitate, and its dependence on θ.