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Three-dimensional phase field simulations of coupled / 0 microstructural evolution and plastic deformation in single crystal Ni-Al are carried out at micrometer scales. Coherent / 0 microstructures and plastic deformation in -channels are described using a single, consistent methodology based on Khachaturyan's phase field microelasticity approach to coherent precipitates and dislocations. In particular, a new set of phase fields is introduced to characterize local density of dislocations from individual active slip systems. To increase the length scale of the phase field simulations, the Kim-Kim-Suzuki (KKS) treatment of / 0 interfaces was adopted. The rafting kinetics, precipitate-matrix inversion process and the corresponding creep deformation are characterized with respect to parameters such as applied stress and lattice misfit. The simulation results on 0 -rafting kinetics and morphological evolution of the / 0 microstructures are compared with available experiment. The model can be used to carry out parametric studies of the effects of material and processing parameters such as alloy composition, external stress and working temperature on 0 -rafting kinetics, morphological evolution and the corresponding creep deformation.

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Additive manufacturing promises a major transformation of the production of high economic value metallic materials, enabling innovative, geometrically complex designs with minimal material waste. The overarching challenge is to design alloys that are compatible with the unique additive processing conditions while maintaining material properties sufficient for the challenging environments encountered in energy, space, and nuclear applications. Here we describe a class of high strength, defect-resistant 3D printable superalloys containing approximately equal parts of Co and Ni along with Al, Cr, Ta and W that possess strengths in excess of 1.1 GPa in as-printed and post-processed forms and tensile ductilities of greater than 13% at room temperature. These alloys are amenable to crack-free 3D printing via electron beam melting (EBM) with preheat as well as selective laser melting (SLM) with limited preheat. Alloy design principles are described along with the structure and properties of EBM and SLM CoNi-base materials.

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