Materials Science and Engineering: A ( IF 6.4 ) Pub Date : 2021-05-04 , DOI: 10.1016/j.msea.2021.141347 Hyejin Song , Minchul Jo , Dae Woong Kim
Hydrogen embrittlement is a phenomenon that causes the deterioration of mechanical properties of steel, such as ductility, owing to hydrogen present inside the material and is a crucial factor that determines the reliability of structural materials. Hydrogen embrittlement is controlled by two kinetics—trapping and diffusion of hydrogen present in the material—and these are affected by microstructural factors such as defects and phases. In this study, microstructures of medium-Mn duplex lightweight steel (Fe-0.5C–12Mn–7Al) and lightweight steel containing 0.1 wt% V and 1 wt% Cu were analyzed, and slow strain rate tensile tests were performed after electrochemical hydrogen charging. The correlation between microstructural evolution and hydrogen embrittlement was analyzed by measuring the amount of hydrogen inside the steel through thermal desorption analysis. Resistance to hydrogen embrittlement was improved in the decreasing order of Cu addition, V addition, and no addition of steel. When V is added, the V-rich carbide acts as an effective hydrogen trapping site, improving the resistance to hydrogen embrittlement despite the majority of hydrogen being inside the specimen. When Cu is added, the B2 particles trap hydrogen in a similar way as done by V-rich carbide, and the solute segregation along the boundaries interferes with hydrogen diffusion. Because Cu is an austenite stabilizer, the fraction of FCC, which is a close packed structure, is high. Thus, the amount of hydrogen entering the specimen is the least under Cu addition, and the corresponding steel shows the best resistance to hydrogen embrittlement. Microstructural factors have a significant effect on hydrogen embrittlement, and by adding V and Cu, it is possible to develop a medium-Mn duplex lightweight steel that can accommodate sufficient deformation even when exposed to a hydrogen atmosphere.
中文翻译:
钒或铜合金双相轻质钢,在室温下具有增强的抗氢脆性
氢脆是由于材料内部存在氢而引起钢的机械性能(例如延展性)下降的现象,并且是决定结构材料可靠性的关键因素。氢脆由两个动力学控制-材料中存在的氢的俘获和扩散-这些受微观结构因素(例如缺陷和相)的影响。在这项研究中,分析了中锰双相轻质钢(Fe-0.5C–12Mn–7Al)和含0.1 wt%V和1 wt%Cu的轻质钢的微观结构,并在电化学氢充填后进行了慢应变速率拉伸试验。通过热解吸分析测量钢内部的氢含量,分析了微观组织演变与氢脆之间的相关性。以Cu添加,V添加和不添加钢的降序提高了耐氢脆性。当添加V时,富含V的碳化物可作为有效的氢捕获位点,尽管大部分氢都在样品内部,但仍提高了抗氢脆性的能力。当添加Cu时,B2粒子以与富V碳化物相似的方式捕获氢,并且沿边界的溶质偏析会干扰氢的扩散。因为Cu是奥氏体稳定剂,所以作为密堆积结构的FCC的比例高。因此,在添加铜的情况下,进入样品的氢量最少,相应的钢显示出最佳的抗氢脆性。微观结构因素对氢脆性具有显着影响,并且通过添加V和Cu,有可能开发出即使暴露于氢气氛也能适应足够变形的中锰双相轻质钢。