scholarly journals Direct Laser Metal Deposition (DLMD) Additive Manufacturing (AM)of Inconel 718 Superalloy: Elemental, Microstructural and Physical Properties Evaluation

2021 ◽  
Author(s):  
Mahmoud Moradi ◽  
Zeynab Pourmand ◽  
Arman Hasani ◽  
Mojtaba Karami Moghadam ◽  
Amir Hosein Sakhaei ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Feed Rate ◽  
Inconel 718 ◽  
Scanning Speed ◽  
Laser Metal Deposition ◽  
Powder Feed Rate ◽  
Direct Laser ◽  
Inconel 718 Superalloy ◽  
The Stability ◽  
Direct Laser Metal Deposition

Abstract In this study direct laser metal deposition (DLMD) technique is adopted for the additive manufacturing (AM) of Inconel 718 Superalloy. To conduct the experiments, a 1 kW fiber laser with a coaxial nozzle head is used. The effects of scanning speed (for two values of 2.5 and 5 mm/s) as well as powder feed rate (for two values of 17.94 and 28.52 g/min) on the process were investigated. Characteristics of the 3D printed wall specimens such as the geometrical dimensions (width and height), microstructure observations, and the microhardness were obtained. In order to study the stability of the 3D manufactured walls, the height stability was considered for the investigation. Optical microscopy (OM), field emission electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and mapping analysis were performed to derive the microstructural features of the additive manufactured samples. The Vickers microhardness test is used to evaluate the hardness distributions of additively manufactured parts. Catchment concept of the powder in DLMD process is used for explaining different trends of the process. Results indicated that, by decreasing the scanning speed, the width and height of the deposited layer increase. The average width of the additively manufactured samples directly depends on the scanning speed and the powder feed rate. Scanning speed has a reverse effect on the height stability; that is, the lower the scanning speed, the larger the stability. Microstructural results showed that because of the solidification process, the alloying elements will be accumulated in the grain boundaries. The non-uniform cooling rate and non-steady solidification rates of molten area in additive manufacturing process, the microhardness values of the additively manufactured samples following a fluctuated trend.

scholarly journals A monitoring framework based on exergetic analysis for sustainability assessment of direct laser metal deposition process

2021 ◽  
Author(s):  
Valeria Selicati ◽  
Marco Mazzarisi ◽  
Francesco Saverio Lovecchio ◽  
Maria Grazia Guerra ◽  
Sabina Luisa Campanelli ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Sustainability Assessment ◽  
Metal Deposition ◽  
Process Efficiency ◽  
Laser Metal Deposition ◽  
Sustainable Solutions ◽  
Direct Laser ◽  
Monitoring Framework ◽  
Exergetic Analysis ◽  
Direct Laser Metal Deposition

Abstract With the constant increase of energy costs and environmental impacts, improving the process efficiency is considered a priority issue for the manufacturing field. A wide knowledge about materials, energy, machinery, and auxiliary equipment is required in order to optimize the overall performance of manufacturing processes. Sustainability needs to be assessed in order to find an optimal compromise between technical quality of products and environmental compatibility of processes. In this new Industry 4.0 era, innovative manufacturing technologies, as the additive manufacturing, are taking a predominant role. The aim of this work is to give an insight into how thermodynamic laws contribute at the same time to improve energy efficiency of manufacturing resources and to provide a methodological support to move towards a smart and sustainable additive process. In this context, a fundamental step is the proper design of a sensing and real-time monitoring framework of an additive manufacturing process. This framework should be based on an accurate modelling of the physical phenomena and technological aspects of the considered process, taking into account all the sustainability requirements. To this end, a thermodynamic model for the direct laser metal deposition (DLMD) process was proposed as a test case. Finally, an exergetic analysis was conducted on a prototype DLMD system to validate the effectiveness of an ad-hoc monitoring system and highlight the limitations of this process. What emerged is that the proposed framework provided significant advantages, since it represents a valuable approach for finding suitable process management strategies to identify sustainable solutions for innovative manufacturing procedures.

Characterization of Colmonoy 227-F Samples Obtained by Direct Laser Metal Deposition

2009 ◽  
Vol 83-86 ◽  
pp. 842-849 ◽  
Author(s):  
Andrea Angelastro ◽  
Sabina L. Campanelli ◽  
Antonio D. Ludovico
Keyword(s):  
Computer Aided Design ◽  
Complex Geometry ◽  
Scanning Speed ◽  
Glass Container ◽  
Metal Deposition ◽  
Laser Metal Deposition ◽  
Metal Powders ◽  
Wide Range ◽  
Direct Laser ◽  
Direct Laser Metal Deposition

Direct Laser Metal Deposition (DLMD) is an emerging technique in the group of Material Accretion Manufacturing (MAM) processes because of the possibility to fabricate and to repair a wide range of metal components with a complex geometry, starting from metal powders. DLMD is a technology which combines computer aided design, laser cladding and rapid prototyping. Fully dense metallic parts can be directly obtained through melting coaxially fed powders with a laser. The success of this technology in the die and tool industry depends on the parts quality to be achieved. An accurate control of the parameters such as laser power, spot diameter, scanning speed and powder mass flow rate is fundamental to obtain the required geometric dimensions and material properties. In this work, the performance of the DLMD process was examined in terms of hardness, porosity, microstructure, and composition. A fitting equipment was built and used for the experiments together with a CO2 laser machine with a maximum power of 3 kW. The material used for experimental tests was Colmonoy 227-F, a Nickel alloy specially designed for glass container mould protection and restoration.

Measurement of Thermal Cycle at Multi-Pass Layer Build-Up with Different Travel Path Strategies during DLMD Process

2019 ◽  
Vol 822 ◽  
pp. 396-403 ◽  
Author(s):  
Stanislav Stankevich ◽  
Andrey Gumenyuk ◽  
Anne Strasse ◽  
Michael Rethmeier
Keyword(s):  
Thermal Cycle ◽  
Infrared Camera ◽  
Absolute Temperature ◽  
Laser Source ◽  
Maximum Temperature ◽  
Laser Metal Deposition ◽  
Thermal Cycles ◽  
Direct Laser ◽  
The Stability ◽  
Direct Laser Metal Deposition

The shape of the parts, created by the technology of direct laser metal deposition (DLMD), is influenced by various parameters, for example, the power and diameter of the laser source spot. The contribution of energy from the laser affects the temperature distribution in the formed layers. The changing temperature in the working area entails a change in the geometry of the layers and affects the stability of the process. In this paper, experiments on the measurement of temperature cycles in the DLMD process with different directions of the filling track are carried out. An infrared camera was used to measure thermal cycles. The correspondence table between the intensity of thermal radiation of the material and the absolute temperature was developed. The experiments are carried out with the filler material 316L. The effect of the maximum temperature on the layer height is shown, and thermal cycles in the formation of layers for different filling strategies are presented.

Investigation on the process and microstructure evolution during direct laser metal deposition of 18Ni300

2018 ◽  
Vol 24 (6) ◽  
pp. 964-972
Author(s):  
Bo Chen ◽  
Yuhua Huang ◽  
Tao Gu ◽  
Caiwang Tan ◽  
Jicai Feng
Keyword(s):  
Grain Size ◽  
Additive Manufacturing ◽  
Microstructure Evolution ◽  
Metal Deposition ◽  
Deposition Method ◽  
Laser Metal Deposition ◽  
Content Type ◽  
Direct Laser ◽  
Single Trace ◽  
Direct Laser Metal Deposition

Purpose Additive manufacturing is a fabrication technology with flexibility and economy. 18Ni300 is one of maraging steels with ultra-high strength, superior toughness, so it is an excellent candidate of structural material. This paper aims to explore the feasibility of using direct laser metal deposition method to fabricate18Ni300, and the evolution of its microstructure and defects is studied. Design/methodology/approach The experiments were conceived from single-trace-single-layer (STSL) test to multi-trace-multi-layers (MTML) test via single-trace-multi-layers (STML) test. The microstructure, defects and mechanical properties were analyzed. Findings The STML results showed that the columnar/equiaxed transformation occurred at the top part and the grain size increased with the layer number increasing, and it was explained by an innovative attempt combining columnar/equiaxed transformation model and the change of grain size. The MTML test with the interlayer orthogonal parallel reciprocating scanning pattern resulted in the grain growing along orthogonal directions; with the increase of overlap rate, the length and the area of the columnar grain decreased. What is more, the later deposition layer had lower micro-hardness value because of heat history. Originality/value Direct laser metal deposition method was a novel additive manufacturing method to manufacture 18Ni300 components, as 18Ni300 maraging steel was mainly manufactured by selective laser melting (SLM) method nowadays. It was useful to manufacture maraging steel parts using direct laser deposition method because it could manufacture larger parts than SLM method. Influence of processing parameters on forming quality and microstructure evolution was studied. The findings will be helpful to understand the forming mechanism of laser additive manufacturing of 18Ni300 components.

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