Effect of Ni, Mo and Mn content on spinodal decomposition kinetics and G-phase precipitation of aged model cast austenitic stainless steels

During ageing, the ferritic phase of Cast Austenitic Stainless Steels (CASS) undergoes decomposition by spinodal and G-phase precipitation, which leads to increasing hardness decreasing impact toughness. Mo-bearing steels are more prone ageing than Mo-free steels. To study effects Ni, Mo, Mn, duplex model alloys were thermally aged at 350 °C 400 °C. The microstructure evolution during was characterized atom probe tomography. Only Ni additions seem affect kinetics. accelerates kinetics regardless presence Mo or Mn. Additions Mn promote precipitation G-phase.