Characterization of hydrogen embrittlement in high-strength fastener steels: mechanical testing and numerical modeling

高强度和超高强度机械紧固件的广泛特点是抗拉强度在1,000到2,000兆帕之间，经常用于关键应用。氢脆造成的损坏可能是材料特性、环境条件、制造缺陷、安装条件和联合设计标准的复杂交互作用造成的。故障的后果从轻微到灾难性不等，甚至会造成生命损失。氢脆(HE)是高强度钢中普遍存在的问题，它是由于元素氢吸收到材料基质中而引起的。高强度钢紧固件中的氢损伤可以归结为可移动氢从晶格位置向应力集中点的迁移，导致裂纹萌生，然后通过裂纹尖端的原子键解聚来扩展裂纹。材料的氢脆效应通常表现为各种类型的慢应变速率试验和增量阶跃载荷试验，它们量化了力学性能的损失，如强度和塑性。

High strength and ultrahigh strength mechanical fasteners are broadly characterized by tensile strengths ranging from 1,000 to 2,000 MPa, and are often used in critical applications. Damage resulting from hydrogen embrittlement can occur by a complex interaction of material characteristics, environmental conditions, manufacturing flaws, installation conditions, and joint design criteria. The consequences of failures can range from minimal to catastrophic, even resulting in loss of life. Hydrogen embrittlement (HE) is a common problem in high strength steel caused by the absorption of elemental hydrogen into the material matrix. Hydrogen damage in high strength steel fasteners can be summarized as a migration of mobile hydrogen from lattice sites to points of stress concentration, resulting in crack initiation followed by crack propagation by atomic bond decohesion at the crack tip. The effect of hydrogen embrittlement in materials is generally characterized by various types of slow strain rate tests and incremental step load tests which quantify the loss of mechanical properties such as strength and ductility.