Temperature mitigates the hydrogen embrittlement sensitivity of martensitic steels in slow strain rates

The joint effect of temperature and strain rate on hydrogen embrittlement properties of martensitic steel was investigated. At 50 & DEG;C, the elongation loss first increases and then, decreases with decreasing the strain rate. It was firstly reported that at the low strain rates, hydrogen embrittlement susceptibility was mitigated by temperature due to an increase in the hydrogen effusion to the surface of the material and the release of a significant amount of hydrogen before the yield point by temperature effect. At 25 & DEG;C, elongation loss increase with decreasing the strain rate, since in lower strain rates, the hydrogen can interact with mobile dislocations, which finally leads to H-induced fracture. The Kurdjumov-Sachs relationship between martensite and austenite was established, and prior austenite EBSD micrographs were obtained. The intergranular crack was observed which can be related to acting prior austenite grain boundaries as an H-induced crack path.

Automated summary

The joint effect of temperature and strain rate on hydrogen embrittlement properties of martensitic steel was investigated. It was found that at 50 °C, the elongation loss initially increased and then decreased with decreasing strain rate. This study provides the first report that at low strain rates, the temperature can mitigate hydrogen embrittlement susceptibility by increasing hydrogen effusion to the material surface and releasing a significant amount of hydrogen before the yield point. At 25 °C, the elongation loss increased with decreasing strain rate, as hydrogen could interact with mobile dislocations at lower strain rates, eventually leading to hydrogen-induced fracture. Additionally, intergranular cracks were observed, which can be attributed to prior austenite grain boundaries acting as paths for hydrogen-induced cracking.