Effect of ageing on phase evolution and mechanical properties of a high tungsten super-duplex stainless steel

► Secondary phases precipitate in a high tungsten SDSS aged between 700 and 900 °C. ► The volume fraction of the sigma phase increases as the holding time increases. ► The evolution of the sigma phase agrees with Johnson-Mehl-Avrami kinetic model. ► The secondary phases enhance the Young's modulus, hardness and strength. ► The ductility decreased significantly with increasing amount of sigma phase.