High temperature tensile deformation of a directionally solidified nickel base superalloy: Role of micro constituents

High temperature tensile deformation behaviour of directionally solidified nickel base superalloy CM 247 DS was studied by conducting tensile tests in the temperature range 25-955 °C and extensive electron microscopic examinations to understand the influence of different phases on tensile behaviour. Micro-constituents, especially carbides and γ−γ′ eutectics influence the deformation and fracture behaviour of alloy CM 247 DS. Cracking of carbide precipitates was extensively observed during tensile deformation at 25 °C. However, tendency of carbide cracking decreased and more carbide-matrix interface de-bonding were observed with increase in test temperature.