ABSTRACT In this paper, the effects of dual-cracks on the CCG behaviour of Hastelloy C276-BNi2 brazed joints were investigated. And the effects of inner crack length, inner crack distance and mismatched material coefficients on the creep crack initiation (CCI) time, CCG rate and creep life were also discussed. The results show that the creep crack can across over the inner crack and propagates continuously. The brazing defects can accelerate the CCG rate, thus leading to the decrease in the creep life and CCG length. With the increases in inner crack length and the decreases in inner crack distance, the CCI time, creep life and CCG length decrease. Longer inner crack distance and shorter defect length can suppress creep crack initiation and propagation. Bigger mismatch factor between base metal and filler metal may avoid the weakening effects of brazing defect on creep life.

中文翻译：

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双裂纹对HastelloyC276-BNi2钎焊接头蠕变裂纹扩展行为的影响

摘要 本文研究了双裂纹对哈氏合金 C276-BNi2 钎焊接头 CCG 行为的影响。并讨论了内裂纹长度、内裂纹距离和不匹配材料系数对蠕变裂纹萌生（CCI）时间、CCG速率和蠕变寿命的影响。结果表明，蠕变裂纹可以跨越内部裂纹并连续扩展。钎焊缺陷会加速CCG速率，从而导致蠕变寿命和CCG长度的降低。随着内裂纹长度的增加和内裂纹距离的减小，CCI时间、蠕变寿命和CCG长度减小。较长的内部裂纹距离和较短的缺陷长度可以抑制蠕变裂纹的萌生和扩展。