Fracture Prediction Based on Evaluation of Initial Porosity Induced By Direct Energy Deposition

2021 ◽  
Author(s):  
Roya Darabi ◽  
Erfan Azinpour ◽  
Jose Cesar de Sa ◽  
Margarida Machado ◽  
Ana Rosanete Reis ◽  
...  
Keyword(s):  
High Performance ◽  
Energy Deposition ◽  
Material Model ◽  
Experimental Methodology ◽  
Initial Porosity ◽  
Stainless Steel 316L ◽  
Present Contribution ◽  
Direct Energy ◽  
Directed Energy ◽  
Porosity Analysis

Additive manufacturing (AM) of metals proved to be beneficial in many industrial and non-industrial areas due to its low material waste and fast stacking speed to fabricate high performance products. The present contribution addresses several known challenges including mechanical behaviour and porosity analysis on directed energy deposition (DED) manufactured stainless steel 316L components. The experimental methodology consisting of metal deposition procedure, hardness testing and fractographic observations on manufactured mini-tensile test samples is described. A ductile fracture material model based on the Rousselier damage criterion is utilized within a FE framework for evaluation of material global response and determination of initial porosity value representing the structure’s nucleating void population. Alternatively, the initial pore sizes are characterized using the generalized mixture rule (GMR) analysis and the validity of the approach is examined against the experimental results.

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 Investigation of hybrid manufacturing of stainless steel 316L components using direct energy deposition

2020 ◽  
pp. 095440542094936 ◽  
Author(s):  
Nikolaos Tapoglou ◽  
Joseph Clulow
Keyword(s):  
Stainless Steel ◽  
Energy Deposition ◽  
Hybrid Manufacturing ◽  
Stainless Steel 316L ◽  
Direct Energy Deposition ◽  
Direct Energy ◽  
Finish Machine ◽  
Metallic Parts ◽  
Non Destructive

Direct energy deposition has been established as one of the methods for additive manufacturing metallic parts. The combination of direct energy deposition capabilities with traditional machining centre capabilities has enabled over the past few years the creation of hybrid manufacturing cells that are able to additively manufacture and finish machine components under one platform. This article investigates the production of geometries using a hybrid, additive and subtractive approach. The parameters for depositing stainless steel 316L are initially investigated followed by an assessment of machinability of the additively manufactured material. Finally, the quality of the deposited and machined material was thoroughly examined with a series of destructive and non-destructive methods.

scholarly journals Hybrid Manufacturing: Influence of Directed Energy Deposition Parameters on Microstructure and Layer Adhesion of Stainless Steel 316L

2019 ◽  
Author(s):  
Jakob D. Hamilton ◽  
Samantha Sorondo ◽  
Andrew Greeley ◽  
Bruce E. Kahn ◽  
Patricia Cyr ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Laser Power ◽  
Energy Deposition ◽  
Scanning Speed ◽  
Hybrid Manufacturing ◽  
Stainless Steel 316L ◽  
Directed Energy Deposition ◽  
Deposition Parameters ◽  
Directed Energy

Abstract In-envelope hybrid manufacturing systems comprised of directed energy deposition (DED) and machining provide flexibility for the fabrication of complex geometries with minimal setup changes. However, for these manufacturing set ups, the effects of deposition parameters such as laser power and scanning speed on the quality of the build remain relatively unexplored. An important aspect for developing components with reliable mechanical properties is a thorough understanding of DED thermodynamics during fabrication. Therefore, DED thermodynamics were defined based on the strengthening properties derived from the thermal gradient (G) and solidification rate (R) of the melt pool. Other factors influencing DED thermodynamics include substrate geometry and surface finish which are expected to affect cooling rates and adhesion, respectively. In this work, stainless steel 316L specimens were fabricated varying laser power intensity, scanning speed, and deposition substrate. The effect of these parameters on the microstructure of the sample components were analyzed. Microstructural evolution at various points within and between layers was studied and correlated to localized hardness. An increase in mechanical properties for fine, equiaxed grains demonstrates the Hall-Petch principle for strengthening of components.

scholarly journals Experimental Investigation of Deposition Pattern on the Temperature and Distortion of Direct Energy Deposition-Based Additive Manufactured Part

2020 ◽  
Vol 10 (21) ◽  
pp. 7653
Author(s):  
Jaemin Lee ◽  
Hyun Chung
Keyword(s):  
Energy Deposition ◽  
Tool Path ◽  
Coordinate Measuring Machine ◽  
Peak Temperature ◽  
Deposition Pattern ◽  
Direct Energy ◽  
Longitudinal Bending ◽  
Measuring Machine ◽  
Direct Metal Tooling ◽  
Directed Energy

The effect of deposition pattern on the temperature and global distortion of Direct Metal Tooling (DMT) based Additive Manufactured (AM) is investigated through the experimental results of laser deposited SUS316. DMT is one of the Directed Energy Deposition (DED) processes. In situ temperature measurements were used to monitor the temperature of the substrates and global distortion patterns were analyzed using CMM (coordinate Measuring Machine) after the deposition. Six different patterns combining long raster and short raster patterns were considered for the case studies. The results showed that the deposition pattern affects the temperature gradient and that the peak temperature of each layer can increase or decrease according to the sequence of the deposition pattern. Also, the pattern of the first layer had a dominant influence on the longitudinal bending deflection that occurs. Based on these results, appropriate tool path schedule can be utilized to control not only the distortion but also the peak temperature of the DMT-based AM parts.

scholarly journals State of the Art in Directed Energy Deposition: From Additive Manufacturing to Materials Design

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 418 ◽  
Author(s):  
Adrita Dass ◽  
Atieh Moridi
Keyword(s):  
Additive Manufacturing ◽  
High Performance ◽  
Energy Deposition ◽  
Future Research ◽  
New Paradigm ◽  
Process Map ◽  
Powder Feed ◽  
Directed Energy Deposition ◽  
Aerospace Medical ◽  
Directed Energy

Additive manufacturing (AM) is a new paradigm for the design and production of high-performance components for aerospace, medical, energy, and automotive applications. This review will exclusively cover directed energy deposition (DED)-AM, with a focus on the deposition of powder-feed based metal and alloy systems. This paper provides a comprehensive review on the classification of DED systems, process variables, process physics, modelling efforts, common defects, mechanical properties of DED parts, and quality control methods. To provide a practical framework to print different materials using DED, a process map using the linear heat input and powder feed rate as variables is constructed. Based on the process map, three different areas that are not optimized for DED are identified. These areas correspond to the formation of a lack of fusion, keyholing, and mixed mode porosity in the printed parts. In the final part of the paper, emerging applications of DED from repairing damaged parts to bulk combinatorial alloys design are discussed. This paper concludes with recommendations for future research in order to transform the technology from “form” to “function,” which can provide significant potential benefits to different industries.

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