以应力腐蚀开裂(SCC)为代表的环境致裂(EAC)是核电一回路安全端异种金属焊接接头在服役过程中的一种重要失效形式，建立物理意义明确的安全端异种金属焊接接头SCC裂纹扩展速率定量预测模型对核电重要结构安全评价具有重要意义。本文以核电安全端异种焊接接头焊接常用的镍基合金600为研究对象，在假定裂尖高应力区焊接材料蠕变是造成SCC裂尖氧化膜破裂的主要因素的前提下，深入探究高温高压水环境中镍基合金应力腐蚀开裂机理，综合运用理论分析、实验研究与数值模拟方法，讨论高应力蠕变对SCC裂尖材料力学性能及其在裂尖氧化膜开裂过程中所产生的影响，最终建立一种基于蠕变致氧化膜破裂的宏微观参量相结合的镍基合金SCC定量预测模型，为提高现有核电安全端焊接结构材料SCC预测精度奠定基础。

Environmental assisted cracking (EAC) represented by stress corrosion cracking (SCC) is an important failure form of dissimilar metal welded joints on the safe end of nuclear power primary circuit during service. The establishment of SCC growth rate model with clear physical meaning is of great significance to the safety evaluation of important nuclear power structures. Nickel-based alloy of dissimilar metal welded joints was adopted as the research object, and on the premise that the crack tip creep of welding material in the high stress zone is the main factor causing the SCC oxide film rupture at crack tip. In-depth exploration of the nickel-based alloys SCC mechanism in high temperature water environments and factors affecting the crack tip oxide film rupture, and combining with theoretical analysis, experimental and numerical simulation to mainly analysis the impact of creep on the material mechanical properties and the effect of the cracking process of the oxide film at SCC crack tip. Finally, based on the creep induced oxide film rupture theoretical considering the macro and micro parameters, the SCC quantitative prediction model is presented for nickel-based alloys in this dissertation, which lays a foundation for improving the SCC prediction accuracy of welding structural materials at safety end of existing nuclear power plants