应力三轴度对淬火态硼钢氢脆敏感性的影响

对硼钢进行电化学充氢和低应变率拉伸,分别画出了纯剪切、单向拉伸及近似平面应变状态下淬火态硼钢充氢前后的应力-应变曲线,并基于等效塑性应变量化了硼钢的氢脆敏感性,研究了应力三轴度对淬火态硼钢的力学性能和氢脆敏感性的影响。用SEM及EBSD表征试样断口的微观组织,根据淬火态硼钢充氢前后断裂模式的变化分析了硼钢在不同应力状态下的氢脆机理。结果表明,淬火态硼钢在剪应力状态下的氢脆机理与拉伸应力状态显著不同,使其氢脆敏感性比拉伸应力状态显著降低。

Effect of Stress Triaxiality on Hydrogen Embrittlement Susceptibility of Quenched Boron Steel B1500HS

The Hydrogen embrittlement (HE) susceptibility of the quenched boron steel B1500HS before and after being electrochemical hydrogen charging by applying different stresses, such as simple shear, uniaxial tensile and analogous plane strain, respectively was investigated via slow strain rate tensile test. Meanwhile, the stress-strain curves for both the H-free and H-charged steels were acquired and then the HE susceptibility of the test steels was calculated based on the equivalent plastic strain to reveal the effects of the stress state on the HE susceptibility of the quenched boron steel. Furthermore, the fracture features of the steels were characterized by SEM and EBSD to analyze the HE mechanism for the different applied stress. The results show that the HE mechanisms of the quenched boron steel by simple shear stress is substantial different to those by tensile stress, which indicated that the HE susceptibility during testing by simple shear stress is much lower than that by tensile stress.