On the impact welding of dissimilar alloys for use in multimaterial skeletal fixation devices

Abstract. Multi-material skeletal fixators appear to be a promising approach to reduce failure due to the high stiffness of standard-of-care fixators. Nevertheless, joining different materials is challenging due to their different properties. High-velocity impact welding, a solid-state welding process, involves the collision of a “flyer” (moving) part with a stationary “target” at very high speed (i.e., hundreds of meters per second). In this paper we present a preliminary experimental campaign to use laser impact welding to join NiTi and Mg alloy Mg-1.2Zn-0.5Ca-0.5Mn (wt%) sheets and the parallel development of a finite element model to allow gathering further insights into the complex phenomena involved in the process. Preliminary results show the deposition of the Mg alloy on NiTi sheets by tuning the joining process conditions and promising results of the numerical model in terms of accordance with experiments: these findings provide the basis for further process optimization, numerical model calibration and the application of a valid protocol for multi-material skeletal fixation devices.