EFFECT OF CARBON ON THE HYDROGEN INDUCED GRAIN BOUNDARY FRACTURE IN IRON.

Abstract

Iron specimens with and without carbon were tensile tested while being charged with hydrogen. A specially prepared high purity iron fractures along grain boundaries after a few percent elongation, otherwise it is completely ductile. The same iron is ductile even under hydrogen charging if doped with carbon of about 20 mass ppm. Tests were also performed on as-quenched and aged specimens with precipitates of epsilon -phase and Fe//3C. The carbon segregated at the grain boundaries prevents grain boundary fracture.