Damping measurements were carried out on two-phase (y-matrix, y'-precipitates) nickel-base alloys containing different volume fractions of y' in order to achieve a better understanding of the strong elastic modus decrease between 1000°C and 1 100°C. For the investigation of the damping a free-free beam flexural vibration technique was applied. Nickel-base alloys with a high volume fraction of y...

Various alloy compositions were cast as single crystals in a Bridgman vacuum induction furnace and creep tested at 980 °C: pure Ni, the equiatomic alloys CoCrNi CrMnFeCoNi (Cantor alloy), single-phase fcc (Ni) solid solution (with composition of matrix-phase CMSX-3 CMSX-4), two-phase Ni-based superalloys CMSX-4. Due to single-crystal state, grain size effects, boundary sliding, diffusion can be...

Abstract Second and third generation single crystal (SX) Ni-based superalloys are considered to be sensitive microsegregation, incipient melting microstructural instability. Thus, their thermodynamic properties stability at high temperatures of key importance. Vapour composition consisting four species has been detected in the temperature range 1453–1573 K. This was found after studies three CM...

Short cracks, extending to the interdiffusion zone, have been observed in platinum-modified nickel-aluminide diffusion coatings on single-crystal CMSX-4 superalloys after these have been subject to short (10 min) rapid thermal cycles. The cracks were revealed after removing the thermally grown oxide formed during cycling on the coating surfaces. Cracking was observed for coatings subject to the...

Creep deformation in < 001 > oriented single crystals of CMSX-3 has been studied at temperatures around 850°C at a stress level of 552 MPa. Detailed observations of the evolution of the dislocation structure during creep have been made. TEM stereo pairs show creep deformation in the matrix phase, leaving the 7’ precipitates undeformed. In previously undeformed crystals there is a brief incubati...

Abstract Combinations of temperature, stress and hot corrosion may cause environmentally-assisted cracking in precipitation-hardened Ni-base superalloys, which is little understood. This research aims to increase current understanding by investigating the effects mechanical on propagation rate during corrosion-fatigue testing CMSX-4, CM247LC DS IN6203DS. The parameters used tests included a hig...