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Astroloy合金中弯曲晶界显著改善了材料的蠕变持久塑性和蠕变裂纹生长抗力。通过尖切口根处蠕变裂纹形成寿命分析与试验比较,证实蠕变J~*积分是控制尖切口(和裂纹)场的有效参量。据此由线性损伤模型和HRR奇异性结合,导出与直晶和弯晶试验结果吻合良好的蠕变裂纹扩展速率表达式: da/dt=Be~(k/n+1)D(x_0)J~(*kn/n+1) 从晶界孔洞形成角度讨论了弯曲晶界蠕变损伤的微观机制。
Bending grain boundaries in Astroloy alloys significantly improve the creep resistance of the material to permanent plasticity and creep crack growth. The analysis of creep crack formation life at the sharp incision root shows that the creep J ~ * integral is an effective parameter for controlling the tip notch (and crack) field. According to this, the expression of creep crack growth rate which is in good agreement with the results of straight crystal and bending test is derived from the combination of the linear damage model and the HRR singularity: da / dt = Be ~ (k / n + 1) D ~ (* kn / n + 1) The microscopic mechanism of creep damage at the grain boundary is discussed from the perspective of the formation of grain boundaries.