Wire Arc Additive Manufacturing of NiTi 4D Structures: Influence of Interlayer Delay

Shape memory alloy structures for actuator and vibration damper applications may be manufactured using wire arc additive manufacturing (WAAM), which is one of the additive manufacturing technologies. Multilayer deposition causes heat accumulation during WAAM, which rises the preheat temperature of the previously created layer. This leads to process instabilities, which result in deviations from the desired dimensions and mechanical properties changes. During WAAM deposition of the wall structure, a systematic research is carried out by adjusting the interlayer delay from 10 to 30 s. When the delay period is increased from 10 to 30 s, the breadth decreases by 45% and the height increases by 33%. Grain refinement occurs when the interlayer delay duration is increased, resulting in better hardness, phase transformation temperature, compressive strength, and shape recovery behavior. This study shows how the interlayer delay affects the behavior of WAAM-built nickel–titanium alloy (NiTi) structures in a variety of applications.