A Crystallographic Model for the Tensile and Fatigue Response for Rene´ N4 at 982°C

Abstract

An anisotropic constitutive model based on crystallographic slip theory was formulated for nickel-base single crystal superalloys. The current equations include both drag stress and back stress state variables to model the local inelastic flow. Specially designed experiments have been conducted to evaluate the existence of back stress in single crystals. The results showed that the back stress effect of reverse inelastic flow on the unloading stress is orientation dependent, and a back stress state variable in the inelastic flow equation is necessary for predicting anelastic behavior. Model correlations and predictions of experimental data are presented for the single crystal supperalloy Rene´ N4 at 982°C.

Microstructure-sensitive modeling of polycrystalline IN 100

“…Viscoelastoplastic anisotropic models with appropriate symmetry have been used to model individual grains or sets of grains with preferred orientation (e.g., directionally solidified polycrystals) are attractive since they can account for the anisotropy of the polycrystalline material at the grain scale (Walker and Jordan, 1985;Sheh and Stouffer, 1990;Shenoy et al, 2005). Explicit models of two phases have been used to model c matrix and the c 0 precipitates in single crystal Ni-base superalloys (Pollock and Argon, 1992;Nouailhas and Cailletaud, 1996;Ohashi et al, 1997;Busso et al, 2000) with a uni-modal precipitate size and a periodic distribution.…”

Grain Scale Crystal Plasticity Model with Slip and Microtwinning for a Third Generation Ni‐Base Disk Alloy

“…The non-Schmid stress  ns is only applicable to the octahedral slip systems within ' particles and governs the transformation from glissile to sessile dislocation cores via dislocation dissociation by implementing the Paidar-Pope-Vitek (PPV) model. The non-Schmid stress is defined as [11] α α α α ns pe pe se se cb cb τ =h τ +h τ +h τ…”

Reduced-Order Constitutive Modeling of Directionally Solidified Ni-Base Superalloys

“…Directionaiiy solidified (DS) Nibase superalloys are often chosen as materials for these hot section components due to their excellent creep resistance and fatigue properties at high temperatures when loaded in the grain growth direction. Since the crystallographic grains are large and the mechanical behavior strongly depends on their orientation, crystal viscoplasticity (CVP) models are ideal for accurately representing the physics of the cyclic deformation response of these materials [1][2][3][4][5][6][7][8][9][10]. However, these constitutive models are computationally expensive especially when extending to predict the effect of uncertainties in process and microstmcture on the component behavior.…”