Modeling of residual stresses in Shape Memory Alloy - Ceramic composites
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Metal-ceramic composites combining Shape Memory Alloys (SMAs) with MAX phase ceramics are gaining interest due to their unique combination of inelastic constituents. Specifically, these composites, intended for extreme environments, are being explored to take advantage of the reversible martensitic transformation associated with SMAs and in-elastic deformations associated with kink band formation in the MAX phases. By using the combination of these mechanisms, a superior composite response may be observed. Specifically, residual stress states may be developed in these composites to take advantage of specific material responses (i.e. improved mechanical response of ceramics under compression). In this work, a microstructurally informed finite element model of this composite is used to study the effect and development of these residual stress states. A recent thermomechanical constitutive model is used for the reversible transformation of the SMA phase while an constitutive approximation is utilized to describe the response of the MAX phases. The effect of additional irrecoverable strains from another phase on the residual stress state is studied and the interaction of the different mechanisms discussed. In this way, it is shown that such deformations increase the residual stress magnitude in the ceramic phase. Furthermore, the impact of the loading path is examined and the dominance of the cooling cycle in developing the residual stresses in the composite is shown. In this context, the micromechanics of the developed residual stress states are discussed.
author list (cited authors)
Lester, B. T., & Lagoudas, D. C.