As the forging counterpart of fusion-based additive processes, additive friction stir deposition offers a solid-state deformation processing route to metal additive manufacturing, in which every vo...

https://www.tandfonline.com/doi/pdf/10.1080/21663831.2020.1847211

Additive friction stir deposition: a deformation processing route to metal additive manufacturing

Welding is a major manufacturing process that joins two or more pieces of materials together through heating/mixing them followed by cooling/solidification. The goal of welding manufacturing is to join materials together to meet service requirements at lowest costs. Advanced welding manufacturing is to use scientific methods to realize this goal. This paper views advanced welding manufacturing as a three step approach: (1) pre-design that selects process and joint design based on available processes (properties, capabilities, and costs); (2) design that uses models to predict the result from a given set of welding parameters and minimizes a cost function for optimizing the welding parameters; and (3) real-time sensing and control that overcome the deviations of welding conditions from their nominal ones used in optimizing the welding parameters by adjusting the welding parameters based on such real-time sensing and feedback control. The paper analyzes how these three steps depend on process properties/capabilities, process innovations, predictive models, numerical models for fluid dynamics, numerical models for structures, real-time sensing, and dynamic control. The paper also identifies the challenges in obtaining ideal solutions and reviews/analyzes the existing efforts toward better solutions. Special attention and analysis have been given to (1) gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) as benchmark processes for penetration and materials filling; (2) keyhole plasma arc welding (PAW), keyhole-tungsten inert gas (K-TIG), and keyhole laser welding as improved/capable penetrative processes; (3) friction stir welding (FSW) as a special penetrative low heat input process; (4) alternating current (AC) GMAW and double-electrode GMAW as improved materials filling processes; (5) efforts in numerical modeling for fluid dynamics; (6) efforts in numerical modeling for structures; (7) challenges and efforts in seam tracking and weld pool monitoring; (8) challenges and efforts in monitoring of keyhole laser welding and FSW; and (9) efforts in advanced sensing, data fusion/sensor fusion, and process control using machine learning/deep learning, model predictive control (MPC), and adaptive control.

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Advanced Welding Manufacturing: A Brief Analysis and Review of Challenges and Solutions

Directed energy deposition (DED) has matured into an essential additive manufacturing (AM) branch. DED has been broadly implemented in the design and fabrication of novel materials. These include metals, ceramics, and composites. Successful DED operation requires a good understanding of many critical phenomena, including laser-material interactions, fundamentals of casting and solidification of alloys, welding metallurgy and joining interfaces, along with microstructure-mechanical properties relations. Also critical are powder flowability, heat transfer, and various machine-related parameters. Several review articles have been published in recent years on metal AM via powder bed fusion (PBF) and DED, focusing on either a specific material system, mapping the recent technologies for AM, or issues related to the deposition process or material properties. Yet, no recent review is dedicated to a comprehensive presentation of material systems, design, fabrication, challenges, and the relationship between microstructures and mechanical properties of various DED'ed material families. Since the DED-based approach is becoming popular to manufacture bimetallic and multi-material structures, repair high-value structures, and alloy design, this comprehensive review focuses on materials design via DED, including a survey of a variety of monolithic and multi-material compositions. Finally, the critical challenges and opportunities in this area are highlighted. 

http://manuscript.elsevier.com/S0921509322003744/pdf/S0921509322003744.pdf

Laser-based directed energy deposition (DED-LB) of advanced materials

Friction stir alloying is primarily employed for the fabrication of surface composite to improve surface properties like hardness, wear resistance, and corrosion resistance without significantly af...

https://journals.sagepub.com/doi/pdf/10.1177/0021998319859427

Fabrication of bulk aluminum-graphene nanocomposite through friction stir alloying:

Laser Additive Manufacturing is relatively new in the manufacturing industry. This paper focuses on the effect of hybrid coatings of Al-Cu-Fe on a grade five titanium alloy (Ti6Al4V) using laser metal deposition (LMD) process at different laser power and scanning speeds. Icosahedral Al-Cu-Fe as quasicrystals are a relatively new class of materials which exhibit unusual atomic structure and useful physical and chemical properties. Ti6Al4V/Al-Cu-Fe composite were analysed using Optical microscopy, Scanning electron microscopy (SEM) with energy dispersive microscopy (EDS), indentation testing, X-Ray Diffraction (XRD), corrosion and wear testing. deposit width and height, heat affected zone (HAZ) height), dilution rate, aspect ratio and powder efficiency of each sample remarkably increased with increasing laser power due to the laser-material interaction. It was observed that there are higher number of aluminium and titanium presented in the formation of the composite. The indentation testing reveals that for both scanning speed of 0.8m/min and 1m/min, the mean hardness value decreases with increasing laser power. It was found that due to dilution effect, a part of Ti entered into molten pool from the substrate. The results indicate that Ti, Al 3 Ti, Ti 3 Al, CuTi 2 can be produced through the in situ metallurgical reactions during the LMD process.

Experimental investigation of laser metal deposited icosahedral Al-Cu-Fe coatings on grade five titanium alloy

This research investigated the evolution of the final microstructural features and wear resistance property that commonly occur within the additive manufactured metal components that are complex to design from titanium alloys and are usually utilised for the various industry applications. The focus of the study encompassed the general knowledge of employing the most common range of additive manufacturing technologies in creating enhanced microstructure and mechanical properties of metal components fabricated by the additive manufacturing processes. This study investigated the characterisation of the performance of wear resistance of Titanium alloy Ti-6Al-4V cladded with Al-Si-Sn-Cu reinforcement which was fabricated by laser metal processing procedures Direct laser metal deposition (DLMD) is the broad manufacturing process characterised under metal additive manufacturing. The metallic substrate material was subjected to numerous processing parameters during fabrication of successive layering, namely the power of the laser beam, the environment in which the deposition took place, the temperature during processing and the rate in which the deposition took place. These important factors have significant influence on the final microstructure and wear resistance performance. CETR - MC reciprocating tribometer was used to analyse the different dadded samples produced by employing the method of direct laser metal deposition (DLMD). A continuous wave of 3 k W ytterbium laser system (YLS) laser was used for this experiment. It was quantified that the resulting wear resistance performance of the titanium alloy specimens produced was dominated by the manufacturing/processing method employed. The results obtained revealed that the wear characteristics of the cladded specimens fabricated by DLMD showed improved Coefficient of Friction (COF). The microstructural study conducted revealed that employing optimized parameters resulted in varied microstructures. Enhanced microstructure and tribological property were attained on account of sound optimized process parameters and suitable selection of reinforcement powders. The properties of the layers critically depend on the manufacturing/processing method and the optimized parameters. It was found that the main microstructural factors such as the porosity due to insufficient fusion, transformation of phases, morphology of the grains, the coarsening process of the microstructure, the heterogeneity in recrystallization and layer banding had a significant influence in the anisotropy and heterogeneity of the microstructure. The shielding phases lead to a decrease in COF and hence proved enhanced tribological property.

The Effects of Silicon and Copper on the Microstructure and Wear Resistance Performance of Al-Si-Sn-Cu/Ti-6Al-4V Composite Coatings

Mechanical and Microstructural Properties of MIG Welded Aluminium Alloy

This paper reports on the effects of heat treatment on 3CR12 and AISI 316 stainless steel grades. Heat treatment was conducted on the steel grades and cooled using two different media; air and water in order to study the effect of each medium on the evolving properties of the samples. The heat treated samples were characterized through the evolving microstructure and hardness. It was found that there was a significant grain size reduction in both the heat treated stainless steel specimens compared to the parent materials. The finer grain sizes were achieved as a result of impediment to growth of one phase by the other. The Vickers microhardness values of the heat treated samples were higher compared to the parent materials due to the fact that each of the steel grades had a proportion of martensitic structures in their microstructures thereby improving the integrity of the material. Keywords—Austenite, Ferrite, Grain size, Hardness, Martensite, Microstructure and stainless steel. I. INTRODUCTION HE continuous search for higher efficiency and productivity across the whole spectrum of manufacturing and engineering industries has warranted that most recent components are exposed to progressively severe environments during routine operation. Critical industrial components are as a result, susceptible to rapid degradation as the parts fail to resist the severities of destructive operating conditions and this has had a huge impact on the industry's economy. In most cases, the fast deterioration of components and their subsequent failure have been found from material damage brought about by unfavorable environmental conditions and by corrosive substances, cyclic stresses and extreme temperatures. Acknowledging that a large number of engineering parts fail catastrophically during service, through corrosion related occurrences, has further promoted this approach and led to the advancement of the stainless steels modification methods using the appropriate heat treatments. Stainless steels represent the most diverse yet complex family of all steels. Stainless steel is a part of a large group of alloys with different properties and consists of a spontaneous layer which forms on their surface and diminishes the rate of corrosion to almost insignificant levels (1). Globally, the demand for stainless steels is increasing at a rate of

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Characterising the effects of heat treatment on 3CR12 and AISI 316 stainless steels

Strengthening the mechanical properties of AA 1100 is important especially for its possible application in bone tissue engineering (BTE). Gypsum is a non-ferrous material already used in the fabrication of scaffolds needed in BTE. A composite emanating from these two materials may provide a mechanically and biocompatible viable option to gypsum (GYP) alone in the fabrication of BTE components. In this study, surface composites with gypsum powder particles as reinforcement in AA 1100 matrix were developed by means of friction stir processing (FS P). Surface analysis of the composite showed well-distributed gypsum particles in the matrix. The average surface roughness measured (Ra = 1.97 μm) is comparable to those found in literature for similar application. The hardness acquired via a Vickers hardness machine showed an improvement (Up to 36.62HV) when compared to as received AA 1100 without reinforcement (23HV). The determined coefficient of friction (COF) for 1 and 10 N were, 1.048 and 0.838 respectively which are sufficiently high and seen as an indication of the roughness of the surface composite. It is found that gypsum powder particles bound well in the AA 1100 matrix.

Microstructural Investigation Of GYP/Al Surface Composites Fabricated By friction Stir Processing

Fractal wear behaviour of gears refers to failure mode of gears as a result of contact mechanics, which occurs while in application. Tooth-to-tooth surface damage usually ensues as a result of variation in excitation energy of the gear. This study therefore investigated the nature of fractal wear encountered by gear tooth with a focus on general fatigue wear, temperature-induced wear and different models for wear predictions. The result of the study showed that tooth surface damage such as fatigue, pitting corrosion and scuffing causes gear failure. Failure due to bending fatigue was observed to contribute to the maximum deflection of the gear tooth during rotation, thus resulting in excessive noise and vibration. Further to this, it was possible to predict the material removal rate of a failed gear using some of the highlighted empirical methods in the study. Based on these models, it will be possible to predict the nature of wear on gear tooth surface and use it during gear design.

Esther T. Akinlabi

Papers

The Effects of Silicon and Copper on the Microstructure and Wear Resistance Performance of Al-Si-Sn-Cu/Ti-6Al-4V Composite Coatings

Mechanical and Microstructural Properties of MIG Welded Aluminium Alloy

Characterising the effects of heat treatment on 3CR12 and AISI 316 stainless steels

Microstructural Investigation Of GYP/Al Surface Composites Fabricated By friction Stir Processing

Fractal Wear Behaviour of Gear Tooth: A Review