How big is the difference between precipitation at twin boundary and normal grain boundary in an alumina-forming austenitic steel during creep at 700 °C?

•After 50 h of creep at 700 °C, coherent twin boundaries were free of precipitate.•The size of precipitates at normal GB was ~150 nm after 50 h of creep.•The precipitates at incoherent twin boundary were ~40 nm at the same time.•After 500 h of creep, the difference in precipitation at all the boundaries were indistinct.