Review of additive manufacturing and densification techniques for the net- and near net-shaping of geometrically complex silicon nitride components

2021 ◽  
Author(s):  
Trevor G. Aguirre ◽  
Corson L. Cramer ◽  
David J. Mitchell
Keyword(s):  
Additive Manufacturing ◽  
Silicon Nitride ◽  
Geometrically Complex ◽  
Near Net Shaping ◽  
Net Shaping

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.

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.

Near‐net shaping of geometrically complex diving knife by semisolid steel casting using ceramic mould system

2011 ◽  
Vol 24 (1) ◽  
pp. 6-12 ◽  
Author(s):  
S Muenstermann ◽  
F Kuethe ◽  
M Buenck ◽  
R Telle ◽  
A Buehrig‐Polaczek
Keyword(s):  
Steel Casting ◽  
Geometrically Complex ◽  
Near Net Shaping ◽  
Net Shaping

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.

Production of UHTC Complex Shapes and Architectures

2013 ◽  
pp. 246-277 ◽  
Author(s):  
Valentina Medri ◽  
Diletta Sciti ◽  
Elena Landi
Keyword(s):  
High Ratio ◽  
Full Density ◽  
Mechanical And Thermal Properties ◽  
Solar Absorbers ◽  
Plasma Sintering ◽  
Fine Microstructure ◽  
Spark Plasma ◽  
Near Net Shaping ◽  
Net Shaping ◽  
Radiant Burners

In spite of the difficult sinterability of Zr and Hf borides and carbides, recent results highlight that these ceramics can be produced with full density, fine microstructure, and controlled mechanical and thermal properties, through different procedures: pressureless sintering and hot pressing with proper sintering aids, reactive synthesis/sintering procedures starting from precursors, and field assisted technologies like spark plasma sintering. More recently, the use of near net shaping techniques and the development of UHTC porous components open the way to further and innovative applications, where the performances, fixed the material, are linked to 2D or 3D architectures and the high ratio of specific surface area to volume of the component and to the features of the porosity itself. Structural lightweight parts, insulator panels, filters, radiant burners, and solar absorbers are some of the possible applications.

Corrections to: Polymer‐derived silicon nitride ceramics by digital light processing based additive manufacturing

2019 ◽  
Vol 102 (12) ◽  
pp. 7769-7770 ◽  
Author(s):  
Min Wang ◽  
Chen Xie ◽  
Rujie He ◽  
Guojiao Ding ◽  
Keqiang Zhang ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Silicon Nitride ◽  
Digital Light Processing ◽  
Nitride Ceramics

Carbon Powder as Additive in Near-Net-Shaping of Mechanical Components through Warm Forming Route

2013 ◽  
Vol 594-595 ◽  
pp. 948-952
Author(s):  
Mujibur M. Rahman ◽  
N.A.A.A. Kadir
Keyword(s):  
Carbon Content ◽  
Density Measurement ◽  
Warm Forming ◽  
Design Parameters ◽  
Carbon Powder ◽  
Forming Temperature ◽  
Die Compaction ◽  
Mechanical Components ◽  
Near Net Shaping ◽  
Net Shaping

This paper presents the study of carbon powder as additive in near-net-shaping of mechanical components through warm forming route. Three design parameters, i.e., carbon content (wt %), forming temperature, and sintering schedule were investigated. Iron powder ASC 100.29 was mechanically mixed with different wt% of carbon and copper powder for 30 minutes to prepare the feedstock. Green compacts were then formed through uni-axial die compaction process at 30°C and 180oC. The defect-free green compacts were then sintered at 1000oC in an argon gas fired furnace at a heating/cooling rate of 5oC/minute for 30, 60, and 90 minutes, respectively. The green samples as well the sintered products were characterized through relative density measurement, radial shrinkage, and microstructure evaluation. The results revealed that excessive carbon content contributed adverse effect to the final quality of the products.

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