Creep behavior of MAR-M 302 Co-base superalloy

MAR-M 302 a Co-base superalloy is currently used for nozzle guide vanes and stator blades in military and commercial aircraft-turbine engines. These components are usually operated at 1073-1273 K. In this study, the uniaxial constant load creep behavior of MAR-M 302 superalloy over temperature range of 1088-1198 K and stress range of 155-321 MPa was investigated. Concerning creep as thermally activated phenomenon, the investigated alloy followed empirical equation (epsilon) over dot = A sigma(n) exp (-Q/RT)with n values ranging mainly from 7 to 10. The mean apparent activation energy was calculated as 525 +/- 29 kJ/mol. The correlation between rupture life and creep characteristics was studied by different prediction methods that are based on the iso-stress lines and those relating the secondary or steady state creep rate to rupture life.