Thermocycling-guided cracking and deformation control in directed energy deposition

In single-step metal Additive Manufacturing (AM) processes, thermal cycling resulting from inappropriate scanning length and deposition height will eventually cause the cracking and deformation of the deposits, which will significantly damage object performance and intended applications. In this work, a unique altering thermal cycling pathway is proposed to efficiently control the cracking and deformation of AMed CuSi3Mn alloys without either using any auxiliary equipment or adjusting the alloy composition. With the help of the Intrinsic Heat Treatment (IHT) caused by secondary or multiple heating and cooling between the subsequent layers and the previous layers, a crack-free cylindric part fabricated by the Gas Metal Arc assisted Directed Energy Deposition (GMA-DED) based on Surface Tension Transfer (STT) is finally obtained, at the same time, the experimental results were verified by the numerical simulation. This further contributes to a superior deposition strategy to control the crack and deformation behavior on the metal AM.