The effect of deformation on the sigma phase occurrence in some stainless steels

Abstract

The effect of deformation on sigma phase occurrence has been studied in two stainless steels, a duplex stainless steel and a ferritic stainless steel. The samples were deformed by rolling at –70⁰C and –196⁰C and subsequently annealed at 7000C for up to 48 hours. Results show that the α → γ₂ reaction precedes the sluggish sigma (σ) phase occurrence. However γ₂ latter becomes enveloped by s and the growth of the former is inhibited. The effect of deformation is increased rate of α → γ₂ reaction. This results in more sites for the σ precipitation; σ precipitates at αγ₂ and α α boundaries. The effect of deformation therefore is to increase the rate of occurrence of σ.



Journal of the Nigerian Association of Mathematical Physics Vol. 8 2004: pp. 327-330