Helium embrittlement in type 304 stainless steel

摘要: Abstract Helium was uniformly injected into small tensile samples of type 304 (austenitic) stainless steel to concentrations 1 × 10−7 and 3 10−5 atom fraction helium. Subsequent testing above 540 °C revealed progressive ductility loss—as measured by total elongation at rupture—with increasing temperature. This effect more severe in with the high helium content where elongations 760 were a third or less those control samples. Yield strengths remained unaltered presence Above 650 °C, grain boundary sliding, which results intergranular cracking, becomes important. The cracks begin as voids on carbide particles act obstacles sliding. In helium, bubbles attach themselves these serve void nuclei, thereby accelerating process. Bubbles also prevalent boundaries, dislocations inclusion than isolated matrix.