Search results for "Turing"
showing 10 items of 2644 documents
Improving surface integrity of additively manufactured GP1 stainless steel by roller burnishing
2020
Abstract Additive manufacturing can rapidly fabricate the desired components by selectively melting and solidifying feedstock, rather than conventional subtractive machining. However, the difference between the two routes in terms of surface integrity of the final component is relevant. This paper presents a strategy to control the surface characteristics of additively manufactured stainless steel by roller burnishing. In particular, process parameters have been carefully selected to improve the surface integrity of the worked material. The quality of the surface has been analyzed in terms of roughness, hardness, microstructure and residual stresses. The overall product endurance under high…
Magnetic field-assisted single-point incremental forming with a magnet ball tool
2021
Abstract This paper describes magnetic field-assisted single-point incremental forming (M-SPIF) with a Nd-Fe-B magnet ball tool. In M-SPIF, the tool driven by magnetic force plastically deforms a sheet. The polarity of the magnet tool helps to make the magnetic force (i.e., forming force) more controllable. In creating a truncated cone, the direction of the magnetic force gradually points more outward as the process progresses, and material is forced outwards from the cone center, increasing thinning in M-SPIF, while the cone center remains undeformed in traditional SPIF. Moreover, M-SPIF creates less localized plastic strain than traditional SPIF while forming the desired geometry.
Design of continuous Friction Stir Extrusion machines for metal chip recycling: issues and difficulties
2018
Abstract Friction Stir Extrusion is an innovative direct-recycling technology developed for metal machining chips. During the process, a rotating die is plunged into a cylindrical chamber containing the material to be recycled. The stirring action of the die prompts solid bonding phenomena allowing the back extrusion of a full dense rod. One of the main weakness of this technology is the discontinuity of the process itself that limits the extrudates volume to the capacity of the chamber. In order to overcome that limitation, a dedicated extrusion fixture has to be developed, keeping into account the concurrent needs of a continuous machine. The geometry of the die has to ensure proper press…
Friction Stir Welding of Ti6Al4V complex geometries for aeronautical applications: a feasibility study
2020
Abstract While Friction Stir Welding (FSW) of aluminium alloys can be considered a mature technology, even for complex joint morphologies, as T joints welded “in transparency”, welding of hard material still presents several open issues. In fact, welding of titanium alloys is a challenging process due to the chemical, mechanical and thermal characteristics of such materials which are subjected to atmosphere contamination resulting in joint hydrogen, oxygen and nitrogen embrittlement; additionally, due to the high melting temperature, large distortion and residual stress are found in joints obtained by traditional fusion welding processes as gas metal arc welding, electron beam welding and l…
Contactless generation of cavitation in high temperature liquid metals and its impact on particle dispersion in solidified iron and steel samples
2021
Abstract A recently developed method for the contactless magnetic generation of cavitation is demonstrated for high-melting-point metals. The approach is based on the floating-zone technique, which is truly contactless and crucible-free as it uses electromagnetic forces. Using this method, ultra-high-temperature ceramic particles, such as TiN, TiB2 and TiC, are admixed in liquid iron and 316L steel. The dispersion and particle refinement caused by cavitation treatment during melting and solidification are investigated. Magnetic fields up to 8 T that correspond to pressure oscillation amplitude of 0.83 MPa are used. The signal emitted by the collapsing bubbles is captured and visualized for …
Dissimilar titanium/aluminum friction stir welding lap joints by experiments and numerical simulation
2016
Dissimilar lap joints were produced by friction stir welding (FSW) out of Ti6Al4V titanium alloy and AA2024 aluminum alloy sheets. The joints, welded with varying tool rotation and feed rate, were studied by analyzing the maximum shear strength, Vickers microhardness and optical observations. A dedicated numerical model, able to take into account the presence of the two different alloys, was used to highlight the effects of the process parameters on temperature distribution, strain distribution, and material flow. The combined analysis of experimental measurements and numerical predictions allowed explaining the effects of tool rotation and feed rate on the material flow. It was found that …
Effect of position and force tool control in friction stir welding of dissimilar aluminum-steel lap joints for automotive applications
2020
Widespread use of aluminum alloys for the fabrication of car body parts is conditional to the use of appropriate welding methods, especially if dissimilar welding must be performed with automotive steel grades. Friction stir welding (FSW) is considered to be a reasonable solution to obtain sound aluminum-steel joints. In this context, this work studies the effects of tool position and force control in dissimilar friction stir welding of AA6061 aluminum alloy on DC05 low carbon steel in lap joint configuration, also assessing proper welding parameter settings. Naked eye and scanning electron microscopy (SEM) have been used to detect macroscopic and microscopic defects in joints, as well as t…
Friction stir extrusion to recycle aluminum alloys scraps: Energy efficiency characterization
2019
Abstract Solid state recycling refers to a group of processes allowing direct recycling of metals scraps into semi-finished product. Their main advantage lies in avoiding the molten state of the material which badly affects the environmental performance of the conventional (remelting based) recycling routes. It is expected that such process category would lower the environmental performance of metals recycling. In this paper, the friction stir extrusion process for aluminum alloy AA 2050 wire production is analyzed under the primary energy demand perspective. The process electrical energy demand is quantified with varying process parameters. An empirical modelling approach was applied and a…
Uncovering Technological and Environmental Potentials of Aluminum Alloy Scraps Recycling Through Friction Stir Consolidation
2020
Conventional metal chips recycling processes are energy-intensive with low efficiency and permanent material losses during re-melting. Solid state recycling allows direct recycling of metal scraps into semi-finished products. It is expected that this process category would lower the environmental performance of metals recycling. Friction Stir Consolidation is a new solid-state technique taking advantage of friction heat generation and severe plastic deformation to consolidate chips into billets. In this research, the feasibility of Friction Stir Consolidation as aluminum chips recycling process is analyzed. Specifically, an experimental campaign has been carried out with varying main proces…
Impact des conditions d'usinage sur la zone du matériau affectée par le procédé
2007
Colloque avec actes et comité de lecture. Internationale.; International audience; Les procédés d'usinage peuvent créer des contraintes résiduelles à la surface des pièces usinées et ainsi modifier la microstructure et la texture de la matière proche de la surface. De tels changements sont importants pour l'étude du comportement des pièces au cours du temps. Il est alors nécessaire de quantifier les contraintes résiduelles, les composantes de texture et de déterminer la microstructure induite par l'usinage pour comprendre et prédire le comportement des surfaces considérées. Dans cette étude, le matériau cuivre pur a été choisi et considéré comme un "système modèle". En tournage, l'influence…