Fatigue crack growth of two carbon steels with different pearlite volume fractions were studied in pressurized gaseous hydrogen environment. Notably, pearlite was found to mitigate hydrogen-assisted fatigue crack acceleration. This positive impact of pearlite was ascribed to ferrite/cementite lamellar aligned perpendicularly to the cracking direction, which functioned as barriers to intermittently arrest the crack propagation. Meanwhile, brittle delamination fracture ensued in the pearlite lamellar lying parallel to the crack-plane increased the crack growth rate and compromised the above positive effect to some extent. The material behavior is rationalized in light of fractographical observations and microstructural analyses of the crack-wake.

研究了两种不同珠光体体积分数的碳钢在加压气态氢环境中的疲劳裂纹扩展。值得注意的是，发现珠光体可以减轻氢辅助疲劳裂纹加速。珠光体的这种积极影响归因于垂直于开裂方向排列的铁素体/渗碳体层状结构，其起到了间歇性阻止裂纹扩展的屏障的作用。同时，平行于裂纹面的珠光体片层发生脆性分层断裂，增加了裂纹扩展速率，并在一定程度上削弱了上述积极作用。根据裂纹尾迹的断口观察和微观结构分析，材料行为被合理化。