Role of Localized Deformation in Irradiation-Assisted Stress Corrosion Cracking Initiation
Role of Localized Deformation in Irradiation-Assisted Stress Corrosion Cracking Initiation
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DOI：
10.1007/s11661-011-0826-5
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
E. West;M. McMurtrey;Z. Jiao;G. Was
中科院分区：
文献类型：
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作者：
E. West;M. McMurtrey;Z. Jiao;G. Was
在高温水溶液和氩气环境中，辐照奥氏体合金的晶间开裂取决于局部晶界应力和变形。拉伸试样用质子辐照剂量为1至7 dpa，然后在高温氩气，模拟沸水反应堆正常水化学，超临界水环境中应变。定量测量证实，（1）粗位错通道的形成，（2）晶界上的不连续滑移，（3）晶界对拉伸轴的高倾斜度，以及（4）晶粒的低变形倾向（以其Schmid和Taylor因子为特征）促进了晶间裂纹的萌生。前两个相关性，以及在位错通道-晶界交叉点的精确位置处形成晶间裂纹是局部变形驱动裂纹萌生的证据。后两个相关性是晶间开裂的证据，在晶界经历升高水平的法向应力促进。
Intergranular cracking of irradiated austenitic alloys depended on localized grain boundary stress and deformation in both high-temperature aqueous and argon environments. Tensile specimens were irradiated with protons to doses of 1 to 7 dpa and then strained in high-temperature argon, simulated boiling water reactor normal water chemistry, and supercritical water environments. Quantitative measurements confirmed that the initiation of intergranular cracks was promoted by (1) the formation of coarse dislocation channels, (2) discontinuous slip across grain boundaries, (3) a high inclination of the grain boundary to the tensile axis, and (4) low-deformation propensity of grains as characterized by their Schmid and Taylor factors. The first two correlations, as well as the formation of intergranular cracks at the precise locations of dislocation channel–grain boundary intersections are evidence that localized deformation drives crack initiation. The latter two correlations are evidence that intergranular cracking is promoted at grain boundaries experiencing elevated levels of normal stress.