Friction-stir techniques are the potential alternative to fusion-based systems for processing and welding metallic alloys and other materials. This review explores the advantages, applications, limitations, and future directions of seven friction-based techniques namely, Additive Friction Stir Deposition (AFSD), Friction Stir Additive Manufacturing (FSAM), Friction Stir Welding (FSW), Friction Stir Processing (FSP), Friction Surfacing (FS), Friction Stir Spot Welding (FSSW), and Friction Stir Lap Welding (FSLW). The basic underlying principle of these processes uses friction as a thermal energy source to weld/process/deposit materials. The common control parameters of all friction stir processing techniques are axial force, rotational speed, and weld or traverse speed. In addition, tool profiles and tool dimensions are known to influence the weld quality. The tool's rotational speed and axial force generate friction between the workpiece and tool material interface, which could plasticize the material. The additive powder bed friction stir process (APBFSP) is another new solid-state manufacturing technique that focus on fabricating the polymer matrix nanocomposites (PNC). In this, a hollow tool like AFSD and the fundamental principle of FSP are combined. The said parameters affect the quantity of material getting deposited/welded. However, weld speed/traverse speed alters the weld quality, and higher traverse speed results in porosity and voids in the welded/deposited/processed region. The only difference between AFSD and other friction stir techniques (FSTs) is that in the AFSD technique, the hollow rotating tool comprises two protrusions with different tool profiles (cylindrical, threaded cylindrical, and tapered cylindrical, square) used. Threaded cylindrical profile and tool steel as the tool material is the most commonly employed in FSTs. Apart from that, tungsten carbide is preferred for hard materials. The working principles and process parameters of FSTs that affect the part quality are discussed in detail. The above review gives the reader an understanding of the domain of FSTs that can be researched further. A summary of some of the potential research works with objectives, process parameters, and outcomes is highlighted. This will provide the readers with an overview of the work carried out by researchers across the globe. Finally, the potential research gaps for future directions to be explored soon across the globe are outlined. 

A Comprehensive Review of Friction Stir Techniques in Structural Materials and Alloys: Challenges and Trends

Microstructure and Nanoindentation response of Si3N4-Reinforced Magnesium-based Composite Synthesized by Powder Metallurgy Route

Purpose




The purpose of this study is to increase the wear resistance of Mg alloy by adding hard ceramic particles to it The inclusion of hard ceramic particles further strengthen the Mg alloy, resulting in higher wear resistance Mg alloys containing Zn, rare earth and Zr exhibit high specific strength and excellent creep resistance, making them suitable for aerospace components such as aircraft gearboxes and generator housings




Design/methodology/approach




In the present study, composites have been produced in situ by using RZ5 mg alloy as matrix and TiC as reinforcement by self-propagating high-temperature synthesis technique The abrasive wear behavior of RZ5 Mg alloy matrix reinforced with TiC particulates has also been examined The pin-on-disc apparatus has been used for the tests The abrasive paper is used as a counter body, and the results are obtained by changing sliding distance and applied load




Findings




A notable enhancement in the wear resistance and mechanical properties of tested composite has been observed as compared to the RZ5 Mg alloy as a matrix There is a uniform increment in the change in weight loss of RZ5-TiC composite with increasing sliding distance and applied load, but it decreases with increasing TiC content The coefficient of friction (µ) also decreases uniformly with an increase in the reinforcement of TiC, but it decreases with an increase in applied load and sliding distance The investigation of the worn composite, which determines dominant wear mechanisms as abrasion and plowing grooves on tested samples, has been done using field emission scanning electron microscopy




Originality/value




The current manuscript provides a detailed abrasive wear analysis of RZ5-TiC composite by using different wear parameters Specifically, extensive experimental data have been provided for RZ5-TiC composite The effects of parameters such as applied load, sliding distance and Wt% of TiC on the weight loss and coefficient of friction of the composites have been analyzed and discussed thoroughly

Effect of wear parameters on dry abrasive wear of RZ5-TiC in situ composite

This work analyzes a novel solid-state manufacturing approach of a friction stir additive manufacturing (FSAM) technique for fabricating multiple layers of alternating gradient composite structure using alternate layers of AA6061-T6 and AA7075-T6 aluminum alloys of 3 mm thickness. The evolution of the microstructure along the build direction and its impact on the tensile and microhardness properties were examined using optical microscopy, tensile tests, and Vickers microhardness tests. Nonuniform microstructures were detected along the build direction, and it was concluded that the most productive part of the construction was the nugget zone, which had fine equiaxed grains. It was identified that the grain sizes and precipitate sizes were affected by the varying thermal cycles created by the multiple passes of the tool. These events were identified as the primary reasons for the increase in strength and hardness of the FSAM build from the lower layer to the upper layer. In the final FSAM build the maximum hardness value was obtained as 182.3 HV and the ultimate tensile strength (UTS) was 420 MPa both of which were identified at the topmost layer. Moreover, the postmortem of the fractured samples revealed that the cause of failure was a combination of both ductile and brittle fractures. The findings of this study suggest that the FSAM approach may be used to fabricate large structures that are free of defects having expected mechanical characteristics and hence the newly fabricated composite can be used as a suitable substitute for the conventional AA6061 material applied in automobile components for its improved performance.

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Novel Technique for Design and Manufacture of Alternating Gradient Composite Structure of Aluminum Alloys Using Solid State Additive Manufacturing Technique

Alloy AZ91D is a leading magnesium alloy used for structural and transport applications. It contains aluminium and zinc as main alloying elements. This work involves a metal matrix composite (MMC) been fabricated using Mg AZ91D alloy and TiC as reinforcement. Wear resistance were evaluated under dry sliding condition at different loads. Wear mechanisms of the composite are basically abrasion-adhesion. The wear resistance of the composite Mg AZ91D/TiC was better than AZ91D Mg alloy. Mechanical property characterization of the composite material revealed an increase in modulus, yield strength and ultimate strength of the composite when compared to AZ91D Mg alloy.

Investigation of mechanical properties and wear behavior of magnesium alloy AZ91D reinforced with TiC

Additive manufacturing comprises layer-by-layer construction of 3D parts using computer controls. This present-day study reveals a list of novel concepts for additive manufacturing, where the addition of material is achieved in solid-state. Materials joined by solid-state techniques exhibits properties beyond those exhibited by material joined by conventional techniques. This has been investigated in both theoretical and experimental manner in length. However, with the development of additive manufacturing techniques, a wide range of possibilities for fabricating complex structures have been identified, which can never be accomplished by conventional techniques. Research on metal-based additive manufacturing has been comparatively less as these products deprive lateral and transverse strength and have issues of anisotropy, making them unfit for structural applications. Moreover, these techniques are not cost-effective. So to overcome these issues, methods incorporating friction into additive manufacturing have been developed. These solid-state techniques use the principle of layer-by-layer deposition. Most of these techniques utilize the principle of selective deposition of materials to form the desired material layer. In this literature review, different advances, approaches, features, and principles of friction-based material joining techniques alongside additive manufacturing are discussed in detail, which recommends new openings for researchers to work in interdisciplinary research to fabricate structures that can exhibit unique properties. This literature portrays an extensive account of the contemporary methods in the fabrication of structures using friction-based additive manufacturing techniques and highlights areas that are worth further research and necessitate a consistent effort on account of the aforementioned disciplines to advance the modernistic technique. Initially, a brief review of different solid-state additive manufacturing techniques is presented, followed by a comprehensive summary of friction stir-based additive manufacturing techniques such as friction assisted seam welding (FASW), additive friction stir (AFS) process, and friction stir additive manufacturing (FSAM) process.

Hari Venkit

Papers

Investigation of mechanical properties and wear behavior of magnesium alloy AZ91D reinforced with TiC

Review on latest trends in friction-based additive manufacturing techniques

Novel Technique for Design and Manufacture of Alternating Gradient Composite Structure of Aluminum Alloys Using Solid State Additive Manufacturing Technique