Residual stress in laser-based directed energy deposition of aluminum alloy 2024: simulation and validation

AbstractSimulations of laser-based directed energy deposition of metals have received increasing interest aimed at reducing the experimental effort to select the proper processing condition for the repair or overhaul of actual components. One of the main issues to be addressed is the evaluation of the residual stress, which may lead to part failure under nominal loading. In this frame and specifically relating to aluminum alloys, few works have been developed and validated. This lack of knowledge is addressed in this paper: namely, the proper approach to simulate the activation of the deposited metal is discussed in case of single deposition and is shifted to a case of multiple depositions over a substrate. The validation of the predicted residual stress is made by comparison with the actual stress resulting from X-ray diffraction.

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Simulation of Laser-assisted Directed Energy Deposition of Aluminum Powder: Prediction of Geometry and Temperature Evolution

Materials ◽

10.3390/ma12132100 ◽

2019 ◽

Vol 12 (13) ◽

pp. 2100 ◽

Cited By ~ 6

Author(s):

Fabrizia Caiazzo ◽

Vittorio Alfieri

Keyword(s):

Energy Deposition ◽

Laser Source ◽

Simulation Tools ◽

Directed Energy Deposition ◽

Reference Shape ◽

Layer Deposition ◽

Deposited Metal ◽

Reliable Model ◽

Aluminum Alloy 2024 ◽

Directed Energy

One of the main current challenges in the field of additive manufacturing and directed energy deposition of metals, is the need for simulation tools to prevent or reduce the need to adopt a trial-and-error approach to find the optimum processing conditions. A valuable help is offered by numerical simulation, although setting-up and validating a reliable model is challenging, due to many issues related to the laser source, the interaction with the feeding metal, the evolution of the material properties and the boundary conditions. Indeed, many attempts have been reported in the literature, although some issues are usually simplified or neglected. Therefore, this paper is aimed at building a comprehensive numerical model for the process of laser-assisted deposition. Namely: the geometry of the deposited metal is investigated in advance and the most effective reference shape is found to feed the simulation as a function of the governing factors for single- and multi-track, multi-layer deposition; then, a non-stationary thermal model is proposed and the underlying hypotheses to simulate the addition of metal are discussed step-by-step. Validation is eventually conducted, based on experimental evidence. Aluminum alloy 2024 is chosen as feeding metal and substrate.

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Investigating the residual stress in additive manufacturing of combined process in powder bed fusion and directed energy deposition

Materials Today Proceedings ◽

10.1016/j.matpr.2021.05.200 ◽

2021 ◽

Author(s):

M. Kumaran ◽

V. Senthilkumar ◽

C.T. Justus Panicker ◽

R. Shishir

Keyword(s):

Residual Stress ◽

Additive Manufacturing ◽

Energy Deposition ◽

Powder Bed Fusion ◽

Combined Process ◽

Powder Bed ◽

Directed Energy Deposition ◽

Directed Energy

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On the Effect of Deposition Patterns on the Residual Stress, Roughness and Microstructure of AISI 316L Samples Produced by Directed Energy Deposition

Lecture Notes in Mechanical Engineering - Progress in Digital and Physical Manufacturing ◽

10.1007/978-3-030-29041-2_26 ◽

2019 ◽

pp. 206-212 ◽

Cited By ~ 2

Author(s):

Gabriele Piscopo ◽

Alessandro Salmi ◽

Eleonora Atzeni ◽

Luca Iuliano ◽

Mattia Busatto ◽

...

Keyword(s):

Residual Stress ◽

Energy Deposition ◽

Aisi 316L ◽

Deposition Patterns ◽

Directed Energy Deposition ◽

Directed Energy

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Modeling of the Effect of the Building Strategy on the Thermomechanical Response of Ti-6Al-4V Rectangular Parts Manufactured by Laser Directed Energy Deposition

Metals ◽

10.3390/met10121643 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1643

Author(s):

Xufei Lu ◽

Miguel Cervera ◽

Michele Chiumenti ◽

Junjie Li ◽

Xianglin Ji ◽

...

Keyword(s):

Residual Stress ◽

Energy Deposition ◽

Heat Transfer Process ◽

Thermally Induced ◽

Directed Energy Deposition ◽

Building Process ◽

Geometric Precision ◽

In Situ Experiments ◽

Stress And Deformation ◽

Directed Energy

Part warpage and residual stress are two of the main challenges for metal additive manufacturing (AM) as they result in lower geometric precision and poor mechanical properties of the products. This work investigates the effect of the building strategy on the heat transfer process and the evolution of the thermally induced mechanical variables in laser directed energy deposition (L-DED) in order to minimize residual stresses and deformations. A 3D finite element (FE) thermo-mechanical model is firstly calibrated through in-situ experiments of rectangular workpieces fabricated by L-DED technology, and, secondly, the coupled thermo-mechanical responses for different process parameters and scanning patterns are discussed in detail. On the calibration stage, the remarkable agreement is achieved between predicted results and experimental data. Regarding the modeling stage, the numerical results indicate that minimization of the part warpage is achieved by reducing the back speed and shortening the scanning lines during the building process. Both residual stress and deformation can be further reduced if preheating the baseplate is added before L-DED.

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