Laser Deposition-Additive Manufacturing of Graphene Oxide Reinforced IN718 Alloys: Effects on Surface Quality, Microstructure, and Mechanical Properties

2019 ◽  
Author(s):  
Yingbin Hu ◽  
Hui Wang ◽  
Weilong Cong
Keyword(s):  
Wear Resistance ◽  
Graphene Oxide ◽  
Additive Manufacturing ◽  
Surface Quality ◽  
Metal Matrix ◽  
Selective Laser Sintering ◽  
Laser Deposition ◽  
Shaping Process ◽  
Near Net Shaping ◽  
Net Shaping

Abstract Owing to its high stiffness and strength, low density, and excellent flexibility, nano-sized graphene oxide (GO) is considered as a competitive material to reinforce metallic materials. Conventional manufacturing methods for GO reinforced metal matrix fabrication include casting and powder metallurgy, both of which demonstrate disadvantages of high reinforcement agglomeration, high cost, and difficulty in fabrication of complex structures. To reduce these problems, it is important to investigate a finely-controlled, cost-saving, and near-net-shaping process for GO reinforced metal matrix manufacturing. Laser additive manufacturing is such a process that mainly includes selective laser sintering / melting (SLS / M) and laser deposition-additive manufacturing (LD-AM). Compared with SLS / M, LD-AM demonstrates parts remanufacturing capability and is capable of fabricating functionally gradient materials. In this investigation, GO reinforced Inconel 718 (IN718) parts, for the first time, are fabricated using LD-AM processes. The effects of GO on flatness, surface roughness, microstructure, microhardness, and wear resistance of LD-AM fabricated GO reinforced IN718 parts are studied. Experimental results show that the introduction of GO is beneficial for enhancing both microhardness and wear resistance but harmful to surface quality of fabricated parts. In addition, the presence of GO has little influence on microstructures.

Laser Engineered Net Shaping Process for 316L/15% Nickel Coated Titanium Carbide Metal Matrix Composite

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
R. S. Amano ◽  
S. Marek ◽  
B. F. Schultz ◽  
P. K. Rohatgi
Keyword(s):  
Cooling Rate ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Point Of View ◽  
Solidification Structure ◽  
Laser Engineered Net Shaping ◽  
Shaping Process ◽  
Net Shaping ◽  
Solid Liquid Interface

This paper presents the investigation of the macrostructure, microstructure, and solidification structure of a 316L/15% nickel coated TiC metal matrix composite produced by the laser engineered net shaping (LENS™) process. The focus of this work was to (1) identify the solidification structure and to estimate growth/cooling rates at the solid/liquid interface, (2) identify and quantify discontinuities in the build structure, and (3) examine the effect of solidification and thermal history on the sample microstructure to further the understanding of the LENS process. A Numerical method was also developed to examine the influence of material type and LENS™ process parameters on the forming of the specific microstructures from thermodynamics and fluid dynamics point of view. Samples of 316L stainless steel were examined, microstructures of samples were used to estimate the corresponding cooling rate, and the cooling rate was compared with the results of numerical modeling. The computational results show reasonable agreement with experimentally determined cooling rate.

scholarly journals Microstructure Evolution of (MgCoNiZnCu)O High Entropy Oxides Using Ceramic Injection Molding

2021 ◽  
Author(s):  
Yipeng ZHAO ◽  
Guoqing CHEN ◽  
Hongwei LI ◽  
Xuesong FU ◽  
Wenlong ZHOU
Keyword(s):  
Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
High Entropy ◽  
Ceramic Injection Molding ◽  
Oxide Powders ◽  
Shaping Process ◽  
Thermal Debinding ◽  
Near Net Shaping ◽  
Net Shaping

Abstract Near net shaping ceramic injection molding process of (MgCoNiZnCu)O high entropy oxides were conducted using commercial precursor oxide powders. Through ball milling, internal mixing, injection molding, solvent and thermal debinding as well as final sintering process, the ceramic products would be obtained with little machining. Compacts prepared are single rock-salt phase based on XRD and EDS Mapping results. Meanwhile, with the increasing of sintering temperature from 900 ℃ to 1050 ℃, particle diffusion rate and densification of samples becomes faster, which finally results relative density and fractured strength of sintered compacts reaching the highest (90.47 % and 77.98 MPa, respectively) in current work. The successfully synthesis of (MgCoNiZnCu)O through ceramic injection molding illustrates this near net shaping process could be a promising route for preparation of high entropy oxides.

An Investigation of Process Parameters on Selective Laser Melting of Nitinol

2013 ◽  
Author(s):  
Jason Walker ◽  
Mohammad Elahinia ◽  
Christoph Haberland
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Material Behavior ◽  
Laser Melting ◽  
Direct Fabrication ◽  
Shape Memory Effects ◽  
Near Net Shaping ◽  
Net Shaping ◽  
Actuation Systems

Nitinol’s superelastic and shape memory effects can be used in passive or active actuation systems. Often used in the aerospace industry, the use of Nitinol for actuation is also growing in the biomedical fields and elsewhere. However, the industry currently lacks the ability to produce complex Nitinol actuators, which is strictly limiting its potential. The extreme difficulty of machining Nitinol complicates manufacturing processes. Furthermore, the transformation temperatures which drive Nitinol’s unique behavior are extremely sensitive to the relative concentrations of nickel and titanium. Therefore, exceptionally tight compositional control during production is necessary to guarantee ideal material behavior. Additive manufacturing (AM) is a near-net-shaping technology which allows for the direct fabrication of complex metallic components. In this way, the (lack of) machinability of Nitinol is no longer an issue because no traditional machining is required during fabrication. Using AM also enables production of 3D geometries that are not possible using traditional techniques. Features such as engineered porosity, hollow parts, curved holes and filigree structures are suddenly realizable. Furthermore, direct CAD fabrication reduces the timescale of the concept-to-prototype transition. A major breakthrough in additive manufacturing came with the development of fiber laser technology in the mid-1990’s, which enables direct melting of manufacturing grade metals into fully dense parts. This technology became known as selective laser melting (SLM). Despite its huge potential, SLM of Nitinol has received little attention from the engineering world. In the present work, two different SLM machines (Realzier SLM 100 and Phenix Systems PXM) are used to develop Nitinol components directly from powder. Adjustment and optimization of the process parameters on the product are analyzed and compared.

scholarly journals Selected Problems of Additive Manufacturing Using SLS/SLM Processes

2021 ◽  
Vol 2021 (1) ◽  
pp. 24-44
Author(s):  
Jerzy Kozak ◽  
Tomasz Zakrzewski ◽  
Marta Witt ◽  
Martyna Dębowska-Wąsak
Keyword(s):  
Additive Manufacturing ◽  
Surface Quality ◽  
Complex Shape ◽  
Selective Laser Sintering ◽  
Dimensional Accuracy ◽  
Metallic Alloys ◽  
Material Structure ◽  
Process Conditions ◽  
Manufactured Products ◽  
Conventional Machining

Abstract Additive Manufacturing (AM) based on Selective Laser Sintering (SLS) and Selective Laser Melting (SLM) is relatively widely used to manufacture complex shape parts made from metallic alloys, ceramic and polymers. Although the SLM process has many advantages over the conventional machining, main disadvantages are the relatively poor surface quality and the occurrence of the material structure defect porosity. The paper presents key problems directly related to the implementation of AM, and in particular the selection and optimization of process conditions. The first section examines the issues of dimensional accuracy, the second surface quality and porosity problem determining the mechanical properties of manufactured products.

Additive Manufacturing of Nitinol Shape Memory Alloys to Overcome Challenges in Conventional Nitinol Fabrication

2014 ◽  
Author(s):  
Jason Walker ◽  
Mohsen Taheri Andani ◽  
Christoph Haberland ◽  
Mohammad Elahinia
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Thermal Characteristics ◽  
Material Behavior ◽  
Direct Fabrication ◽  
Shape Memory Effects ◽  
Near Net Shaping ◽  
Net Shaping ◽  
Actuation Systems ◽  
Compositional Control

The pseudoelastic and shape memory effects of NiTi can be used in passive or active actuation systems. Often used in the aerospace industry, the use of NiTi for actuation is also growing in the biomedical fields and elsewhere. However, it’s potential in industry is currently limited by the inability to produce complex NiTi parts. Conventional manufacturing processes are complicated by the extreme difficulty associated with machining NiTi. Furthermore, the transformation temperatures which drive the unique behavior of NiTi as a shape memory alloy are extremely sensitive to the relative concentrations of nickel and titanium. Therefore, exceptionally tight compositional control during production is necessary to guarantee ideal material behavior. Additive manufacturing (AM) is a near-net-shaping technology which allows for the direct fabrication of complex metallic components. By utilizing the AM processing principle, the poor machinability of NiTi is no longer an issue. Using AM also enables production of 3D geometries that are not possible using traditional techniques. Furthermore, direct CAD fabrication reduces the timescale of the concept-to-prototype transition. In the present work, an SLM machine (Phenix Systems PXM) is used to develop NiTi components directly from powder. The thermal characteristics and shape memory functionality of SLM NiTi components is demonstrated.

Additive Manufacturing of Shape Memory Devices and Pseudoelastic Components

2013 ◽  
Author(s):  
Christoph Haberland ◽  
Mohammad Elahinia ◽  
Jason Walker ◽  
Horst Meier ◽  
Jan Frenzel
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Raw Material ◽  
Processing Route ◽  
High Quality ◽  
Manufacturing Method ◽  
Structural And Functional Properties ◽  
Shape Memory Effects ◽  
Near Net Shaping ◽  
Net Shaping

Processing of Nickel-Titanium shape memory alloys (NiTi) is by no means easy because all processing steps can strongly affect the properties of the material. Hence, near-net-shaping technologies are very attractive for processing NiTi due to reduction of the processing route. Additive Manufacturing (AM) provides especially promising alternatives to conventional processing because it offers unparalleled freedom of design. In the last 5 years AM of NiTi received little attention from academics and researchers and, therefore, is far from being established for processing NiTi today. This work is to highlight the current state of the art of using the AM technique Selective Laser Melting (SLM) for processing high quality NiTi parts. For this reason, fundamentals for SLM processing of NiTi are described. It is shown in detail that a careful control of process parameters is of great importance. Furthermore, this work characterizes structural and functional properties like shape recovery, referring to the shape memory effect in Ti-rich SLM NiTi, or pseudoelasticy in Ni-rich SLM NiTi. It is shown that both types of shape memory effects can be adjusted in SLM NiTi by the choice of the raw material and processing strategy. By comparing the properties of SLM NiTi to those of conventionally processed NiTi, this work clearly shows that SLM is an attractive manufacturing method for production of high quality NiTi parts.

Material Efficiency and Economics of Hybrid Additive Manufacturing

2021 ◽  
Author(s):  
Peter Francis Reginald Elvis ◽  
Senthilkumaran Kumaraguru
Keyword(s):  
Additive Manufacturing ◽  
Case Studies ◽  
Cost Effective ◽  
Machining Process ◽  
Total Production ◽  
Material Efficiency ◽  
Aerospace Applications ◽  
Feature Based ◽  
Near Net Shaping ◽  
Net Shaping

Abstract In the past few years, Hybrid Additive Manufacturing has emerged to take advantage of both Additive Manufacturing and Subtractive Manufacturing processes and also to overcome the limitation of one process with the other. In aerospace applications, material wastage has become an issue in conventional machining process which reflects in total production cost and time. Especially, when dealing with expensive materials, conventional processes lack material efficiency with high buy-to-fly ratio which results in increased material cost. This paper deals with Hybrid Additive Manufacturing involving two different volume partitioning strategies — (i) Feature-based volume partitioning method (ii) Stock-based near net-shaping volume partitioning method to discuss the economics and material efficiency of Hybrid Additive Manufacturing process via simple cost estimator (formulated from the existing literature) by comparing these two volume partitioning strategies through suitable case studies — (i) Turbine blade and (ii) Impeller. From the results, it was found that the feature-based volume partitioning method was found to be material efficient and cost effective than the stock based near net shaping volume partitioning method in both the case studies.

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