Observations of Facet Formation in Near-α Titanium and Comments on the Role of Hydrogen
Observations of Facet Formation in Near-α Titanium and Comments on the Role of Hydrogen
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DOI：
10.1007/s11661-010-0507-9
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发表时间：
2011-04-01
影响因子：
2.8
通讯作者：
Williams, J. C.
中科院分区：
文献类型：
--
作者：
Pilchak, A. L.;Williams, J. C.
在静态载荷、连续循环、驻留疲劳载荷和应力腐蚀裂纹（SCC）失效的钛合金断裂表面上经常观察到刻面特征。虽然在不同的加载条件下形成的小平面似乎定性相似，有显着差异的小平面的空间和晶体取向以及小平面表面形貌的细微差异。本研究比较和对比了Ti-8Al-1 Mo-1V合金在各种载荷条件（循环、蠕变、SCC和驻留）下的刻面，主要目的是了解驻留疲劳期间裂纹萌生和刻面生长的机制。使用定量倾斜断口和电子背散射衍射的小平面的空间和晶体学取向进行了测定，而小平面形貌进行了检查，使用超高分辨率扫描电子显微镜。总的来说，实验观察表明，氢可能发挥重要作用，在小面形成和加速小裂纹的增长率在停留疲劳加载。
Faceted features are frequently observed on the fracture surfaces of titanium alloys that have failed by static loading, continuous cycling, dwell fatigue loading, and stress corrosion cracking (SCC). Although the facets formed under different loading conditions seem qualitatively similar, there are significant differences in the spatial and crystallographic orientations of the facets as well as subtle differences in facet surface topography. The current study compares and contrasts facets for various loading conditions (cyclic, creep, SCC, and dwell) in the Ti-8Al-1Mo-1V alloy with the primary motivation being to understand the mechanisms of crack initiation and faceted growth during dwell fatigue. The spatial and crystallographic orientations of the facets were determined using quantitative tilt fractography and electron backscatter diffraction, whereas facet topography was examined using ultra-high-resolution scanning electron microscopy. Collectively, the experimental observations suggest that hydrogen may play an important role in facet formation and accelerating small crack growth rates during dwell fatigue loading.