This paper proposes a new in-situ hydrogen (H) charging bending technique to investigate the susceptibility to hydrogen embrittlement (HE) of high strength steels with limited ductility. The methodology is tested with generic martensitic Fe–C steels with a carbon (C) content of 0.2 wt%, 0.4 wt% and 1.1 wt%, respectively. The in-situ bending technique is developed to evaluate the hydrogen susceptibility of these brittle materials and is compared to uncharged samples as a reference. Moreover, as a crucial step in the validation of the technique, a comparison with conventional in-situ tensile testing for the most ductile material (i.e. Fe-0.2C) is performed. The bending results show that charging with H causes a significant ductility loss, which is characterized by a transition from a microvoid (Fe-0.2C), intergranular (Fe-1.1C) or mixed (Fe-0.4C) fracture surface for the uncharged samples to a hydrogen induced cleavage fracture appearance with additional cracking. The transition to the cleavage fracture type is found to be caused by the Hydrogen Enhanced Plasticity Mediated Decohesion mechanism, indicating that hydrogen is preferentially trapped at packet or block boundaries in high carbon steels without alloying additions. The fracture surface of the Fe-0.2C alloy after in-situ tensile testing was very similar to the fracture surface obtained after in-situ bending testing, which indicates that the fracture mode during bending is mainly dominated by the tensile field. This supports the applicability of the in-situ bending technique for intrinsically brittle materials.

本文提出了一种新的原位氢（H）装料弯曲技术，以研究延展性有限的高强度钢对氢脆（HE）的敏感性。该方法论已用碳含量分别为0.2 wt％，0.4 wt％和1.1 wt％的普通马氏体Fe-C钢进行了测试。开发了原位弯曲技术以评估这些脆性材料的氢敏感性，并将其与不带电样品进行比较作为参考。此外，作为验证该技术的关键步骤，与最易延展的材料（即Fe-0.2C）的传统原位拉伸测试进行了比较。弯曲结果表明，用H充电会导致显着的延展性损失，其特征是从微孔（Fe-0.2C），晶间（Fe-1.1C）或混合（Fe-0）过渡。4C）不带电的样品的断裂表面具有氢诱导的分裂断裂外观，并带有额外的裂纹。发现向裂解断裂类型的转变是由氢增强塑性介导的脱粘机理引起的，这表明氢优先被捕集在高碳钢的小块或大块边界，而没有添加合金。原位拉伸测试后的Fe-0.2C合金的断口表面与原位弯曲测试后的断口非常相似，这表明弯曲过程中的断口模式主要由拉伸场决定。这支持了原位弯曲技术对固有脆性材料的适用性。发现向裂解断裂类型的转变是由氢增强的可塑性介导的脱粘机理引起的，这表明氢优先被捕集在高碳钢中的块状或块状边界，而无需添加合金。原位拉伸测试后的Fe-0.2C合金的断口表面与原位弯曲测试后的断口非常相似，这表明弯曲过程中的断口模式主要由拉伸场决定。这支持了原位弯曲技术对固有脆性材料的适用性。发现向裂解断裂类型的转变是由氢增强的可塑性介导的脱粘机理引起的，这表明氢优先被捕集在高碳钢中的块状或块状边界，而无需添加合金。原位拉伸测试后的Fe-0.2C合金的断口表面与原位弯曲测试后的断口非常相似，这表明弯曲过程中的断口模式主要由拉伸场决定。这支持了原位弯曲技术对固有脆性材料的适用性。这表明在高碳钢中，氢优先被捕集在小块或大块的边界，而没有添加合金。原位拉伸测试后的Fe-0.2C合金的断口表面与原位弯曲测试后的断口非常相似，这表明弯曲过程中的断口模式主要由拉伸场决定。这支持了原位弯曲技术对固有脆性材料的适用性。这表明在高碳钢中，氢优先被捕集在小块或大块的边界，而没有添加合金。原位拉伸测试后的Fe-0.2C合金的断口表面与原位弯曲测试后的断口非常相似，这表明弯曲过程中的断口模式主要由拉伸场决定。这支持了原位弯曲技术对固有脆性材料的适用性。