Effect of helium implantation at 533–573 K on tensile properties of 9Cr martensitic steels

Abstract

The effects of helium implantation (300 appm) at 533–573 K on the tensile properties of 9Cr-1MoVNb (modified 9Cr-1Mo) and low-activation 9Cr-2W martensitic steels were investigated. Tensile tests were carried out with miniature specimens from room temperature to 973 K. The helium implantation caused an increase in strength at all the test temperatures. Implantation produced defects, but defect clusters were not found in as-implanted specimens and in specimens tested below 773 K. Small bubbles were observed above 873 K. While ductility loss was greater at higher test temperatures, the fracture mode was found to be ductile and transgranular.