γ′-cutting as rate-controlling recovery process during high-temperature and low-stress creep of superalloy single crystals

Non-Isothermal Creep Behavior of a Second Generation Ni-Based Single Crystal Superalloy: Experimental Characterization and Modeling

“…In this context, it is assumed that the internal stress is smaller for shorter t OEI , allowing more dislocations to enter the γ matrix channels during subsequent creep at 1050°C. According to previous studies [26,35,36], this leads to an increased minimum strain rate. This assumption is also in full agreement with the experimental results obtained for an OEI performed at t pre = 0, where minimum creep rates do not depend on t OEI .…”

“…It was reported in literature that under isothermal high temperature/low stress conditions, only a limited number of matrix dislocations can enter the γ channel due to bs σ [34], and that further deformation is only possible if dynamic recovery of these matrix dislocations occurs by γ' cutting events [26,35,36]. It was suggested by these authors that the minimum creep rates min ε & directly result from the number of γ' cutting events.…”

High-temperature creep of single-crystal nickel-based superalloy: microstructural changes and effects of thermal cycling

“…Since we are working with rafted structures, recovery mechanisms of the γ dislocations are required to allow macroscopic deformation of the superalloy. It has been repeatedly proposed that such recovery may occur by dislocations crossing the γ' rafts [29,30]. Thus, we focus our study on the dislocation microstructure within the rafts.…”

Incorporating strain gradient effects in a multiscale constitutive framework for nickel-base superalloys

“…Experimental work [19,35,[38][39][40][41][42][43][44][45][46] has shown that precipitate shearing becomes important at temperatures above 950 o C and at larger strains (later stages of steady-state creep). At lower temperatures considerable stresses in the range of 500 to 600 MPa are required to initiate particle shearing.…”