韧性体应力腐蚀机理模型

Mechanism Models of Stress Corrosion Cracking in Ductile Solids

工业上常见的应力腐蚀(SCC)是一种具有低应力脆性解理特征的失效模式,同时SCC机理一直是近百年来的科学难点和研究热点。结合最新研究进展,综述了韧性体SCC机理模型。宏观上,SCC通常由敏感材料、特定环境和应力三因子构成,其失效准则遵循Griffith理论。微观上,重点分析了近几十年提出的SCC机理的构型、适用性和局限性。大体上,SCC微观机理主要包括滑移溶解模型、择优溶解模型、膜致解理模型、腐蚀促进塑性变形模型和环境断裂一致性模型。尽管各模型对SCC的物理化学本质尚存争议,但从阳极溶解到膜破裂、位错滑移到脆性解理、氢的促进作用到电负性粒子的耦合作用,各模型对SCC的认识已逐步深化,已深入至原子尺度,具有重要理论意义和应用价值。此外,还展望了SCC前沿科学与应用前景。

Stress corrosion cracking(SCC),often occurring in industries,is a failure mode with the feature of brittle cleavage at low stress levels.Meanwhile,the SCC mechanism is always a tough and focused scientific issue during about one hundred years.Based on recent research progress,SCC mechanism models specific in ductile solids are reviewed in this paper.Macroscopically,the three factors on SCC consist of susceptible materials,specific environment and stress as usual.The failure criterion of SCC accords with the Griffith’s theory.Microscopically,this work primarily analyzes models,suitability and limit of SCC mechanisms proposed in the past several decades.In principle,the microscopic SCC mechanisms are composed of the slip dissolution model,the selective dissolution model,the film induced cleavage model,the corrosion enhanced plasticity model and the uniformed environment assisted cracking model.It is obvious that the physical and chemical SCC essence is controversial until now.However,from anodic dissolution to film rupture,from dislocation slipping to brittle cleavage and from the hydrogen-enhanced effect to the synergistic effects of electronegative particles,the development of the models gradually tents to atomic scales.As a consequence,the SCC models are fairly valuable in the aspects of theory and application.Besides,the prospects of advanced SCC science and application are also done at the final.