The microstructure and tensile strength at 1 100 ℃ of high W cast superalloy with W content of 12.0%

13.0%

15.5% and 16.5%（mass fraction）were investigated.The results show that with the increase of W content

the secondaryγ′phase is grown up into irregular shapes from regular square shape

and volume fraction is increased from 51.1%to 61.8%firstly and then decreased to 55.3%.The high temperature strength at 1 100℃of the superalloy is increased from 405 MPa to 488 MPa firstly and then decreased to 433 MPa.The alloy with low W content exhibits low tensile strength

which is mainly attributed to insufficient reinforcement of secondaryγ′phase

while for high W content superalloy

decrease of strength is attributed to the precipitation ofα（W）induced insufficient reinforcement of secondaryγ′phase.The tensile strength of alloys with W content of 13.0% and 15.5% has a higher strength

which reach 440

4

88 MPa at 1 100 ℃.