| Popis: |
Slow strain rate tensile tests, and some fatigue tests, were run at room temperature in the environments of air, liquid mercury and hydrogen. The hydrogen was generated electrolytically, with the charging and testing commencing simultaneously. The specimens were quenched and tempered to a range of hardness levels. The embrittlement by hydrogen and by mercury differed in several aspects. In hydrogen alone, there was a loss of tensile strength, a marked strain rate sensitivity, and a crack progression of transgranular to intergranular to microvoid coalescence. In mercury, the crack initiation was intergranular. It is believed that the hydrogen induced transgranular cracking is plasticity related with hydrogen penetration occurring at an enhanced rate. This situation would not arise with mercury. |
