海洋工程超高强钢腐蚀疲劳裂尖微结构演化与力化关联性研究

The failure of materials and components under multiple marine environments has become one of the bottlenecks in the development of marine engineering and its equipment manufacturing. It has always been a hot area of research at domestic and abroad and a problem to be solved. This project is to meet the great demand of service safety performance of structural materials used in the marine resource development projects in China. Three key problems on the corrosion fatigue of super high-strength marine steel involve: the influence factors of corrosion fatigue crack propagation and interaction mechanism, the characteristic of microstructure and its evolution at the tip of corrosion fatigue crack, the macro and micro mechanism of corrosion fatigue crack growth. Taking the new domestic F690 super high-strength and toughness ship plate steel as the research object, the corrosion fatigue crack growth behavior will be systematically studied in the simulated seawater environment. The goal of the research is to reveal the nature of the interaction between the electrochemical and mechanical behavior during corrosion fatigue crack propagation, to figure out the effect of local microstructural morphological characteristics and scaling factors at the crack tip on corrosion fatigue crack growth, to establish the corrosion fatigue crack growth mechanism corresponding to micro evolution and macro law. Finally, this project will provide a theoretical basis for the safe service of new marine engineering materials.

多重海洋环境下材料和构件的腐蚀及损伤已成为海洋工程及其装备制造发展的制约瓶颈之一，也一直是国内外研究的热点和亟待解决的问题。本项目针对我国海洋资源开发工程中对结构材料服役安全性能的重大需求，围绕海洋工程超高强钢腐蚀疲劳涉及的3个关键问题：腐蚀疲劳裂纹扩展的控制因素和相互作用机制，裂纹尖端局部微结构特征及其演化规律，腐蚀疲劳裂纹扩展的宏微观机制。以国产新型F690级高强韧船板钢为研究对象，对其在模拟海水环境中的腐蚀疲劳裂纹扩展行为开展系统研究。研究目标是：揭示材料腐蚀疲劳裂纹扩展过程中力学与电化学行为交互作用的本质，阐明裂尖局部微观组织结构的形态特征和尺度因素对腐蚀疲劳裂纹扩展的影响趋势，建立反映微观过程与宏观规律相对应的腐蚀疲劳裂纹扩展机制，最终为海洋工程新材料的安全服役提供理论依据。

多重海洋环境下材料和构件的腐蚀及损伤已成为海洋工程及其装备制造发展的制约瓶颈之一，也一直是国内外研究的热点和亟待解决的问题。本项目针对我国海洋资源开发工程中对结构材料服役安全性能的重大需求，围绕海洋工程超高强钢在模拟海水环境中的腐蚀疲劳裂纹扩展行为开展系统研究。采用自主研发、可对缺口试样进行电化学充氢的实验装置，对试验样品进行电化学充氢，后进行纳米压痕和纳米蠕变试验，确定材料局部氢-位错-晶界交互作用机制；采用自主研发的基于杠杆的慢拉伸应力腐蚀实验装置，搭配水化在线监测系统、直流电压降系统和电化学工作站，对样品进行充氢条件下的裂纹扩展速率试验，确定氢含量与材料裂纹扩展速率的相关性规律，揭示了材料腐蚀疲劳裂纹扩展过程中力学与电化学行为交互作用的本质；通过多尺度组织结构表征分析，研究了材料力学行为与材料微观组织结构及环境条件之间的规律性联系，阐明了裂尖局部微观组织结构的形态特征和尺度参数对腐蚀疲劳裂纹扩展的影响趋势，建立了反映微观过程与宏观规律相对应的腐蚀疲劳裂纹扩展机制，为海洋工程新材料的安全服役提供理论依据。