Austenite content and dislocation density in electron-beam welds of a stainless maraging steel

The volume fraction of austenite and dislocation density in electron beam weld joints of a martensitic-austenitic age-hardenable Cr-Ni-Mo-Ti-Al stainless steel were investigated using neutron diffraction. Experiments were performed on a high-resolution diffractometer which resolved microstrains of the order of 10(-4). The effect of post-weld heat treatment on austenite content and dislocation density was investigated. As in other maraging steels, the maximum volume fraction of austenite was obtained after quenching and intercritical annealing. Dislocation densities computed on the base of mean-square microstrain values were about 10(11) cm(-2). These densities were systematically higher in martensite than in austenite, with very small differences between the weld metal and base metal.