scholarly journals Numerical Modeling Design for the Hybrid Additive Manufacturing of Laser Directed Energy Deposition and Shot Peening Forming Fe–Cr–Ni–B–Si Alloy

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4877
Author(s):  
Xiaoyu Zhang ◽  
Dichen Li ◽  
Weijun Zhu
Keyword(s):  
Temperature Field ◽  
Additive Manufacturing ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Shot Peening ◽  
Energy Deposition ◽  
Hybrid Process ◽  
Forming Process ◽  
Directed Energy Deposition ◽  
Directed Energy

Hybrid additive manufacturing is of great significance to make up for the deficiency of the metal forming process; it has been one of the main trends of additive manufacturing in recent years. The hybrid process of laser directed energy deposition (laser DED) and shot peening is a new technology combining the principles of surface strengthening and additive manufacturing, whose difficulty is to reduce the interaction between the two processes. In this paper, a new model with a discrete phase and fluid–solid interaction method is established, and the location of the shot peening point in the hybrid process is optimized. The distributions of the temperature field and powder trajectory were researched and experiments were carried out with the optimized parameters to verify simulation results. It was found that the temperature field and the powder trajectory partly change, and the optimized injection point is located in the stress relaxation zone of the material. The densities and surface residual stresses of samples were improved, and the density increased by 8.83%. The surface stress changed from tensile stress to compressive stress, and the introduced compressive stress by shot peening was 2.26 times the tensile stress produced by laser directed energy deposition.

An approach to reduce stress and defects: a hybrid process of laser cladding deposition and shot peening

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaoyu Zhang ◽  
Dichen Li ◽  
Jiale Geng
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Laser Cladding ◽  
Shot Peening ◽  
Hybrid Process ◽  
Layer By Layer ◽  
Residual Tensile Stress ◽  
Forming Process ◽  
Content Type ◽  
Thermal Forming

Purpose Laser cladding deposition is limited in industrial application by the micro-defects and residual tensile stress for the thermal forming process, leading to lower fatigue strength compared with that of the forging. The purpose of this paper is to develop an approach to reduce stress and defects. Design/methodology/approach A hybrid process of laser cladding deposition and shot peening is presented to transform surface strengthening technology to the overall strengthening technology through layer-by-layer forming and achieve enhancement. Findings The results show that the surface stress of the sample formed by the hybrid process changed from tensile stress to compressive stress, and the surface compressive stress introduced could reach more than four times the surface tensile stress of the laser cladding sample. At the same time, internal micro-defects such as pores were reduced. The porosity of the sample formed by the hybrid process was reduced by 90.12% than that of the laser cladding sample, and the surface roughness was reduced by 43.16%. Originality/value The authors believe that the hybrid process proposed in this paper can significantly expand the potential application of laser cladding deposition by solving its limitations, promoting its efficiency and applicability in practical cases.

scholarly journals High Performance NbMoTa–Al2O3 Multilayer Composite Structure Manufacturing by Laser Directed Energy Deposition

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1685
Author(s):  
Hang Zhang ◽  
Zihao Chen ◽  
Yaoyao He ◽  
Xin Guo ◽  
Qingyu Li ◽  
...  
Keyword(s):  
Smart Materials ◽  
Composite Structure ◽  
Composite Structures ◽  
High Performance ◽  
Energy Deposition ◽  
Coefficient Of Thermal Expansion ◽  
Multilayer Composite ◽  
Forming Process ◽  
Directed Energy Deposition ◽  
Directed Energy

The conventional method of preparing metal–ceramic composite structures causes delamination and cracking defects due to differences in the composite structures’ properties, such as the coefficient of thermal expansion between metal and ceramic materials. Laser-directed energy deposition (LDED) technology has a unique advantage in that the composition of the materials can be changed during the forming process. This technique can overcome existing problems by forming composite structures. In this study, a multilayer composite structure was prepared using LDED technology, and different materials were deposited with their own appropriate process parameters. A layer of Al2O3 ceramic was deposited first, and then three layers of a NbMoTa multi-principal element alloy (MPEA) were deposited as a single composite structural unit. A specimen of the NbMoTa–Al2O3 multilayer composite structure, composed of multiple composite structural units, was formed on the upper surface of a φ20 mm × 60 mm cylinder. The wear resistance was improved by 55% compared to the NbMoTa. The resistivity was 1.55 × 10−5 Ω × m in the parallel forming direction and 1.29 × 10−7 Ω × m in the vertical forming direction. A new, electrically anisotropic material was successfully obtained, and this study provides experimental methods and data for the preparation of smart materials and new sensors.

scholarly journals Directed energy deposition additive manufacturing of functionally graded Al-W composites

2021 ◽  
Vol 39 ◽  
pp. 101845
Author(s):  
J.P. Kelly ◽  
J.W. Elmer ◽  
F.J. Ryerson ◽  
J.R.I. Lee ◽  
J.J. Haslam
Keyword(s):  
Additive Manufacturing ◽  
Energy Deposition ◽  
Functionally Graded ◽  
Directed Energy Deposition ◽  
Directed Energy

scholarly journals Working distance passive stability in laser directed energy deposition additive manufacturing

2019 ◽  
Vol 161 ◽  
pp. 86-94 ◽  
Author(s):  
James C. Haley ◽  
Baolong Zheng ◽  
Umberto Scipioni Bertoli ◽  
Alexander D. Dupuy ◽  
Julie M. Schoenung ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Energy Deposition ◽  
Passive Stability ◽  
Directed Energy Deposition ◽  
Directed Energy ◽  
Working Distance

Towards Computational Modeling of Temperature Field Evolution in Directed Energy Deposition Processes

2018 ◽  
Author(s):  
Jianyi Li ◽  
Qian Wang ◽  
Panagiotis (Pan) Michaleris
Keyword(s):  
Temperature Field ◽  
Thermal History ◽  
Energy Deposition ◽  
Deposition Process ◽  
Final Part ◽  
Laser Source ◽  
Heat Sources ◽  
Analytical Computation ◽  
Directed Energy Deposition ◽  
Directed Energy

In modeling and simulating thermo-mechanical behavior in a directed energy deposition process, it often needs to compute the temperature field evolved in the deposition process since thermal history in the deposition process would affect part geometry as well as microstructure, material properties, residual stress, and distortion of the final part. This paper presents an analytical computation of temperature field evolved in a directed energy deposition process, using a single-bead wall as an illustrating example. Essentially, the temperature field is computed by superposition of the temperature fields generated by the laser source as well as induced from each of the past beads, where the transient solution to a moving heat source in a semi-infinite body is applied to describe each individual temperature field. For better characterization of cooling effect (temperature contribution from a past bead), a pair of positive and negative virtual heat sources is assigned for each past bead. In addition, mirrored heat sources through a reflexion technique are introduced to define the adiabatic boundaries of the part being built and to account for the substrate thickness. In the end, three depositions of Ti-6AL-4V walls with different geometries and inter-layer dwell times on an Optomec® laser engineered net shaping (LENS) system are used to validate the proposed analytical computation, where predicted temperatures at several locations of the depositions show reasonable agreement with the in situ temperature measurements, with the average prediction error less than 15%. The proposed analytical computation for temperature field in directed energy deposition could be potentially used in model-based feedback control for thermal history in the deposition, which could affect microstructure evolution and other properties of the final part.

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