Influence of the characteristic of recrystallization grain boundary on the formation of creep cracks in a directionally solidified Ni-base superalloy

► Crack was observed at some of the high angle RX GBs with the misorientation angle more than 20°. ► Not all of high angle RX GBs cracked. ► It is difficult for cracks to form at low angle RX GBs and twin boundary. ► Crack formation is related to the dislocation mobility at GB.