Fatigue-crack propagation behavior of type 304 stainless steel in a liquid sodium environment

The fatigue crack growth of Type 304 stainless steel in a liquid sodium environment at 800 and 1000°F was characterized using a linear-elastic fracture mechanics approach. Tests were conducted in low (< 2.0 ppm) and high (20-40 ppm) oxygen sodium and the results were compared to those of tests conductedin vacua and in air. Similar crack propagation characteristics in air at room temperature and at elevated temperatures in sodium and vacuum is evidence that the thermally activated component of crack propagation observed in air is an environmental effect. Related work on environmental effects on fatigue or crack propagation properties are reviewed and discussed.