Rate dependent ductility and damage threshold: Application to Nickel-based single crystal CMSX-4
Abstract
A phenomenological damage model is proposed to account for the strain rate dependency of thedamaging processes at high temperature. Mechanical softening during tertiary creep andmonotonic tension are modeled by an isotropic scalar internal variableD, whose evolution isdescribed using a rate damage law dD / td = ⋯ governed by visco-plasticity and accounting forthe enhancement by stress triaxiality. A novel rate sensitive damage threshold is introduced inorder to reproduce the rate dependency of the onset of damaging processes. Damage evolution iscoupled with the visco-plasticity model developed by the same authors for single crystal super-alloys and accounting for microstructural evolution (like γ'-rafting and coarsening) in Desmoratet al. (2017). The curves presented in this article are identified at 1050 °C for the Ni base singlecrystal superalloy CMSX-4 but the proposed rate sensitive threshold modeling can be applied toother alloys showing a rate sensitive damage onset, as for example the single crystal superalloysMC2 but also the polycrystalline aggregate AD 730TM.
Domains
Fluid mechanics [physics.class-ph] Material chemistry Acoustics [physics.class-ph] Automatic Electromagnetism Reactive fluid environment Electric power Polymers Acoustics [physics.class-ph] Biomechanics [physics.med-ph] Materials and structures in mechanics [physics.class-ph] Thermics [physics.class-ph] Vibrations [physics.class-ph] Mathematical Physics [math-ph] Quantum Physics [quant-ph]
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