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Bonding and Cladding of Composite Materials
Published in Pankaj Agarwal, Lokesh Bajpai, Chandra Pal Singh, Kapil Gupta, J. Paulo Davim, Manufacturing and Industrial Engineering, 2021
Rotary swaging is a precision forming process usually used for the production of tubes, bars and other cylindrical components (Kocich et al. 2017; Kocich et al. 2018). This type of forging process belongs to the net-shape-forming process where the net shape is obtained with minimal process and cutting. Rotary swaging is a forging process used for producing solid cylindrical, hollow and solid parts where the axis can be elongated. Rotary swaging is suitable for manufacturing various parts in aerospace, automotive and defence industries like hollow steering columns, guide shafts, fasteners etc. Rotary swaging increases the durability of the components compared to that of the other processes. Swaging is normally a cold working process, but in some cases, it can be used in a hot working condition. The rotary swaging process involves two categories: (i) the extrusion of the workpiece, forcing it into the die and in order to reduce the diameter of the workpiece and (ii) using two or more dies to hammer the workpiece to be able to lessen the diameter.
Sustainability in Joining
Published in R. Ganesh Narayanan, Jay S. Gunasekera, Sustainable Material Forming and Joining, 2019
Joining by forming is a separate category of joining of metallic structures in which plastic deformation is used for joining. Mechanical interlocking happens during such joining methods. Since fumes and emissions are not generated, protective gases and fluxes are not used, the process is a better option for sustainable manufacturing. However, the strength of the joint should be checked as there is no metallurgical bonding between the joining structures. Rotary swaging, joining by end forming, SPR, and clinching belong to the category. SPR and clinching are discussed in the previous section. Zhang et al. (2014) performed rotary swaging (Figure 3.8) method to join the tubes of different diameters. Rotary swaging is a type of incremental forming process, where dies around the workpiece move simultaneously in both radial and axial directions relative to the workpiece. The swaging dies perform high-frequency radial movement with short strokes. The process is capable of joining different materials, with different interface characteristics. It is a clean joining process because of no fume generation and no external consumables used. But the process is restricted to join tubes of different diameters.
From titanium ore extraction and processing to its applications in the transportation industry — an overview
Published in CIM Journal, 2023
C. Siemers, F. Haase, L. Klinge
Independent of the melting procedure, the final ingots are typically deformed by (hot) forging, rotary swaging, rod extrusion, or rolling to form bars, rods, plates, sheets, or other semi-finished products (Peters & Leyens, 2002). Because these operations are normally performed in air, oxide formation is observed at the surface, and oxygen can diffuse into the metal at the oxide-metal interface of processed parts. Oxygen is a strong α-stabilizer, and α-case formation can occur at the subsurface–a (partial) transformation to the α-phase. Along with the phase transformation, increased hardness, reduced toughness, minimized fatigue properties, and notch sensitivity are observed in the α-case due to the additional dissolved oxygen. Therefore, the oxide layer and the α-case are generally removed by stripping or grinding before application or further processing like semi-finished product manufacturing (Lütjering & Williams, 2007). After deformation, a recrystallization treatment is usually carried out and, if required, a subsequent aging procedure is performed to produce the final microstructure (see next section).
Sinter-swage processing of an Al-Si-Mg-Cu powder metallurgy alloy
Published in Canadian Metallurgical Quarterly, 2022
M. F. Wilson, I. W. Donaldson, D. P. Bishop
As in industrial extrusion operations, the grains were elongated in the direction of swaging, when viewed longitudinally[30]. Evidence of metal flow is also present when the edges of the microstructure are viewed, as would be expected from a hot deformation operation.
Atomistic simulation of the stacking fault energy and grain shape on strain hardening behaviours of FCC nanocrystalline metals
Published in Philosophical Magazine, 2019
Lin Yuan, Peng Jing, Rajiv Shivpuri, Chuanlong Xu, Zhenhai Xu, Debin Shan, Bin Guo
Nanotwins are a particular type of lamellar grain. Present techniques to fabricate lamellar grains [14] including shot peening, air blast shot peening, sandblasting, surface nano-cystallisation and hardening, ultrasonic shot peening, surface mechanical attrition treatment, surface mechanical grinding treatment, particle impact processing and cryogenic burnishing. Hu et al. [15] fabricated a high strength, ultrafine-grained aluminium alloy with a lamellar structure via cryomilling and consolidation (hot isostatic pressing), followed by a two-stage thermomechanical processing approach (e.g. high temperature rotary swaging and room temperature high strain rate extrusion). The lamellar band consisted of multiple ultrafine grains connected by low angle GBs which facilitated dislocation glide through low angle GBs. Dislocations accumulated within the band enabled high strength as well as high uniform elongation. The size effect found in experiments is attributed to grain gradients. A dependence of yield strength on size is discovered in the absence of strain gradients. Creer et al. [16] present the results of uniaxial compression experiments on Au without stress/strain gradients. A significant flow stress increase is observed, up to several GPa, which is thought to be controlled by dislocation starvation. In their experiments, strain hardening is not significant. Uchic et al. [17] measure the plastic yielding of single crystals at micrometre-sized dimensions for three different metals. The results indicate short periods of stable flow with low work-hardening rates, separated by increments of nearly elastic loading, and they attributed the work hardening to dislocation interaction. Wang et al. [18] directly observe deformation twinning in nc tungsten by in situ high-resolution TEM. Twinning is the dominant deformation mechanism and loading orientation dominates the competition between twinning and dislocation slip. Large strain plasticity in single crystalline Si nanowires at room temperature is directly observed in axial tensile in situ high-resolution TEM experiments by Han et al. [19]. High dislocation density induces plasticity. Emission of dislocations and formation of disordered crystalline structures develop the continuous disordered lattice, resulting in the amorphous structure and large strain plasticity. A continuous and reversible lattice deformation is observed during bending of Ni nanowires by in situ TEM [20]. The shear strain is as high as 34.6%, which is approximately four times that of the theoretical elastic strain limit for unconstrained loading. The deformation mechanism is phase transformation, from original fcc to bcc and finally to a reoriented fcc structure. Our previous study on layer-grained silver reveals a strain softening behaviour at 0.01 K [21]. Ag has low stacking fault energy and the situation for other metals with distinct stacking fault energy is still unknown.