With the stricter international regulations on CO₂ emissions, fuel economy, and auto-safety, the application of novel materials with both higher strength and lower weight is becoming a major technical issue in automotive industries. Among the various lightweight concepts, ultra-strong GIGA STEEL with a tensile strength of more than 2 GPa is a major breakthrough in light of the remarkable weight reduction of vehicle without a decrease in auto-safety. Despite the outstanding mechanical performance, hydrogen embrittlement induced by aqueous and/or atmospheric corrosion is a serious problem that has restricted the application of steel to auto-parts. This study reports that such a critical challenge can be overcome by Ni-alloying, which leads to a lower cathodic reduction rate on the steel surface and slower H-infusion kinetics in the steel matrix. In contrast to the beneficial effects of Ni-alloying, conflicting results can be obtained when steel with a higher Ni content (≥1 wt.%) is exposed to neutral-corrosive environments, but the results have not been verified using conventional metallurgical approaches. This paper proposes a mechanism for these conflicting results, and provides a new and economic strategy for superior resistance to corrosion-induced hydrogen embrittlement, by making optimal use of Ni-alloying of ultra-strong steel.

有了关于CO ₂的更严格的国际法规排放，燃油经济性和汽车安全性方面，应用强度更高且重量更轻的新型材料已成为汽车行业的主要技术问题。在各种轻量化概念中，抗拉强度超过2 GPa的超高强度GIGA钢是一项重大突破，因为它显着减轻了车辆的重量，却没有降低汽车的安全性。尽管具有出色的机械性能，但是由于水和/或大气腐蚀引起的氢脆是一个严重的问题，已经限制了钢在汽车零件中的应用。这项研究报告表明，镍合金可以克服这样的严峻挑战，这可以降低钢表面的阴极还原速率，并降低钢基质中的H注入动力学。与镍合金的有益作用相反，当具有较高的Ni含量（≥1 wt。％）的钢暴露于中性腐蚀环境时，可以获得矛盾的结果，但是该结果尚未使用常规的冶金方法进行验证。本文针对这些矛盾的结果提出了一种机理，并通过优化利用超强钢的镍合金化，为抗腐蚀引起的氢脆性提供了新的经济策略。