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本文从断裂力学角度,讨论了弯曲晶界对Astroloy合金蠕变断裂特性的影响。 通过的特殊热处理得到弯曲幅度大、普遍性好的弯曲晶界。弯曲晶界最重要的影响是它显著提高材料的持久塑性和蠕变裂纹生长抗力。 通过切口根处蠕变裂纹形成寿命试验分析方法,证明了蠕变J~*积分是控制切口(从而裂纹)场的有效参量。据此应用J~*参量控制的HRR奇异性与线性损伤模型相结合进行分析,导出蠕变裂纹扩展速率表达式,最后讨论了弯曲晶界的影响。
In this paper, the effect of bending grain boundaries on the creep rupture characteristics of Astroloy alloys is discussed from the point of view of fracture mechanics. Through the special heat treatment to get bending large, universal good bending grain boundaries. The most important effect of bending the grain boundaries is that it significantly increases the material’s ductile plasticity and creep crack growth resistance. By creep crack formation at the incision root life test analysis method, it is proved that the creep J ~ * integral is an effective parameter for controlling the notch (and hence the crack) field. Based on this, the HRR singularity of J ~ * parametric control is analyzed in combination with the linear damage model, and the expression of creep crack propagation rate is derived. Finally, the effect of bending grain boundaries is discussed.