Deformation Mechanisms in NiTi-Al Composites Fabricated by Ultrasonic Additive Manufacturing

Abstract

Thermally active NiTi shape memory alloy (SMA) fibers can be used to tune or tailor the effective coefficient of thermal expansion (CTE) of a metallic matrix composite. In this paper, a novel NiTi-Al composite is fabricated using ultrasonic additive manufacturing (UAM). A combined experimental-simulation approach is used to develop and validate a microstructurally based finite element model of the composite. The simulations are able to closely reproduce the macroscopic strain versus temperature cyclic response, including initial transient effects in the first cycle. They also show that the composite CTE is minimized if the austenite texture in the SMA wires is h001i B2 , that a fiber aspect ratio [10 maximizes fiber efficiency, and that the UAM process may reduce hysteresis in embedded SMA wires.Keywords SMA Á Composite material Á Coefficient of thermal expansion Á Finite element analysis Á Ultrasonic additive manufacturing Á Thermomechanical behavior

Design for Additive Manufacturing: Trends, opportunities, considerations, and constraints

“…For example, it is possible to create custom mixes of powders and binders [353], to alternate feedstock materials [81] [357], and to embed fibers [33][65] [67] in order to create in situ composites, increase mechanical strength, modify the thermal expansion coefficient [67], and obtain electrically tuneable stiffness [281]. Similarly, it is possible to control the porosity, microstructure, and material properties of metal, polymer, and ceramic parts through the choice of materials, process parameters, and build orientation [75][292] [353][362] [365].…”

State-of-the-art of fiber-reinforced polymers in additive manufacturing technologies

“…65–67 In Monaghan et al., 24 embedded optical fibers into a metal coating were presented. In literature, 68–70 NiTi fibers in an Al matrix were described. It was pointed out that fiber-reinforcement contradicts the shrinkage of the matrix material after the welding process.…”

Ultrasonic Welding of Nickel with Coarse and Ultrafine Grained Structures

“…Li and Soar [13] obtained a SiC fiber-reinforced composite with Al-alloy matrix. Chen et al [14] designed by FEM modeling and fabricated a NiTi-Al matrix composite with a minimized coefficient of thermal expansion.…”