Microstructure and properties of isothermal forged superalloy GH710

Superalloy GH710 is very difficult to be forged by conventional methods.It creates uneven micro-structure and physical properties,or even a cracked forging.In order to solve the problem,the isothermal forging processes were developed for superalloy GH710.The microstructure and mechanical properties of isothermal forged superalloy GH710 were studied.The results show that the fine grains and good mechanical properties can be achieved for GH710 by isothermal deformation.When superalloy GH710 is isothermal forged at 1100 ℃ with the reduction of 50%and 70%,it has excellent mechanical properties and the rupture life is increased obviously.For example,the notched stress-rupture life at 815 ℃ is more than 100 h and smooth stress-rupture life at 980 ℃ is more than 80 h.The investigated isothermal forging technology scheme can be used for developing GH710 turbine disc and the achieved isothermal forged GH710 disc exhibits satisfactory properties.