Creep Fracture Mechanism of a Single Crystal Nickel Base Alloy Under High Temperature and Low Stress

This paper reports the creep behavior of a nickel-based single crystal alloy and the creep fracture mechanism under high temperature and low stress was discussed. The creep curves were analyzed with the Kelvin model. The retardation spectra suggest that the involved atoms during creep need more relaxation time to achieve the viscous flow, nevertheless, the creep under the stress of 120 MPa may be caused by the mismatch of dislocation motion and visco-plastic deformation. The fracture morphologies of crept alloys indicate that the nickel base single crystal alloy presents micro-pore aggregation fracture mechanism under the condition of high temperature and low stress creep.