Experimental Study and Kinetic Calculation on Migration of γ/α Interface Boundary During High Temperature Aging for 2205 Duplex Stainless Steel

Aging treatments in the temperature range of 1 000 to 1 200 °C for different time intervals (10, 30, and 60 min) in a solution-treated 2205 duplex stainless steel (DSS) are carried out respectively. The migration of γ/α interface boundary after different aging treatments is measured by optical metallograph and calculated by DICTRA software. The experimental results are in agreement with calculated ones. The migration of γ/α interface boundary with increased keeping time depends on the chemical potential of chromium in each phase. At aging temperature of 1 100 C, the back diffusion effect of chromium results in the opposite direction migration of γ/α interface. Therefore, the ferrite volume fraction is lower at first and then it is higher after 1 800 s diffusion.