Abstract
A new method of controlling the residual stress in laser directed energy deposition additive manufacturing (DED AM) products proposed based on constraints used in manufacturing and the substrate design. The simulation results of the residual stress, which were validated with the experimental measured data, showed that weaker constraints on the substrate could greatly decrease the residual stress in the laser DED AM products. In addition, by designing local reduced thickness regions into the substrate, such as long strip holes or support legs, the residual stress in DED AM products could be further decreased. In this study, when long strip holes were designed in the substrate, the tensile residual stress was decreased by 28%. An even smaller amount of residual stress was achieved when the design structure was changed to support legs. The tensile residual stress decreased by more than 30%. The fewer support legs, the smaller the residual stress. The residual stress in DED AM products could be well-controlled by design, while the stiffness can be weakened with fewer constraints.
Highlights
In recent years, laser directed energy deposition additive manufacturing (DED AM), an advanced technology that builds materials layer by layer, has developed quickly and gained increasing attention [1–3]
The results showed that the high tensile residual stresses in the deposition layers could be clearly decreased and even changed into compressive stress after the heat treatment
In the DED AM process, the local high temperature gradient leads to inhomogeneous expansion in the heating process, which is the cause of residual stress and distortion
Summary
Laser directed energy deposition additive manufacturing (DED AM), an advanced technology that builds materials layer by layer, has developed quickly and gained increasing attention [1–3]. In DED AM, the heat energy density absorbed by the deposition layer is the key factor in the local temperature gradient and in inducing high residual stress. It can be greatly influenced by the deposited materials, laser power, laser scanning speed, laser beam radius, and structure of the substrate. Though the influencing factors and the method of controlling the residual stress in DED AM products have been systematically studied, less attention has been given to research on the effect of the substrate structure on residual stress. The method for controlling the residual stress in DED AM products was presented by designing the substrate structure
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
