Search results for "metals"
showing 10 items of 2013 documents
Failure maps to assess bearing performances of glass composite laminates
2018
Aim of this article is the assessment of the bearing mechanical performances of pin-loaded glass laminates as function of their geometrical configuration. To this concern, 32 specimens having different hole diameter (D), laminate width (W), and hole center to laminate free edge distance (E) have been tested under bearing conditions. The maximum bearing stress and the stress-displacement curves were analyzed as function both of hole to laminate free edge distance E and hole diameter D. Moreover, an experimental 2D failure map was created by placing the experimental results (i.e., the kind of failure mechanism occurred for each geometrical configuration) in the plane E/D versus W/D ratios. In…
Weld quality prediction in linear friction welding of AA6082-T6 through an integrated numerical tool
2016
Abstract A numerical and an experimental campaign were carried out with varying oscillation frequency and interface pressure. The local values of the main field variables at the contact interface between the specimens were predicted by a Lagrangian, implicit, thermo-mechanical FEM model and used as input of a dedicated Neural Network (NN). The NN, integrated in the FEM environment, was designed in order to calculate both a Boolean output, indicating the occurrence of welding, and a continuous output, indicating the quality of the obtained solid state weld. The analysis of the obtained results allowed three different levels of bonding quality, i.e., no weld, sound weld and excess of heat, to…
Influence of friction stir processing conditions on the manufacturing of Al-Mg-Zn-Cu alloy/boron carbide surface composite
2018
Abstract Surface metal matrix composites were synthesized via friction stir processing (FSP) on the surface of aluminium alloy 7075 (AA 7075) sheets by incorporating B4C particles (B4CP). The influence of tool rotational speeds, powder particle sizes, and change in tool travel direction between FSP passes on particle distribution and resulting properties were studied in detail. Change in tool travel direction, decreased tool rotation speed and fine B4C particles enhanced B4CP distribution and wear properties thereof. Wear resistance of composites were doubled on account of the B4CP distribution and resultant several strengthening mechanisms.
The application of the random balance method in laser machining of metals
2008
International audience; Features peculiar to laser technology offer some advantages over more traditional processes, but, like all processes, it has its limitations. This article studies the limitations of laser machining of metals, and quantifies, through an experimental design method, the influence of operating parameters on productivity and on the quality of the machined surface. Three study materials were used: an aluminium alloy, stainless steel and a titanium alloy. An initial reading of the results indicates that productivity depends mainly on the frequency of the laser pulse and that the aluminium alloy behaves differently from the other two. The quality of the machined surface, jud…
A numerical model for Wire integrity prediction in Friction Stir Extrusion of magnesium alloys
2017
Abstract A numerical model for the prediction of the wire quality produced by the novel direct machining chip recycling technique known as Friction Stir Extrusion (FSE) is presented. Wire microstructure and wire integrity have been predicted by embedding in the code the equations enabling the calculation of the Zener-Hollomon parameter as well as the W parameter of the Pivnik-Plata solid bonding criterion. The proposed model, developed for the AZ31 magnesium alloy using the commercial simulation package DEFORM, is 3D Lagrangian, thermo-mechanically coupled with visco-plastic material behavior. The model was first validated against experimental temperature measurements and then used to predi…
Effect of active heating and cooling on microstructure and mechanical properties of friction stir–welded dissimilar aluminium alloy and titanium butt…
2019
A butt joint configuration of AA6061–pure Ti was welded using friction stir welding (FSW) with an assisted cooling and heating conditions, aiming to attain a flawless joint. Cooling-assisted friction stir welding (CFSW) was carried out with a different cooling medium such as CO2, compressed air and water at controlled flow rate. However, heating-assisted friction stir welding (HFSW) was performed with heating source of GTAW torch just before FSW tool at different current density. Prepared specimens were subjected to optical microscopy (OM), scanning electron microscopy (SEM) and electrodischarge spectroscopy (EDS) for microstructural characterizations. The tensile strength and microhardness…
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 …
Aluminum to titanium laser welding-brazing in V-shaped grooveI
2017
International audience; Laser assisted joining of AA5754 aluminum alloy to T40 titanium with use of Al-Si filler wires was carried out. Continuous Yb:YAG laser beam was shaped into double spot tandem and defocalized to cover larger interaction zone in V shaped groove. Experimental design method was applied to study the influence of operational parameters on the tensile properties of the joints. Microstructure examination and fractography study were carried out to understand the relation between local phase content and fracture mode.Within defined window of operational parameters, statistically important factors that influenced the strength of T40 to AA5754 joints in V groove configuration w…
On the complete interface development of Al/Cu magnetic pulse welding via experimental characterizations and multiphysics numerical simulations
2021
Abstract A complex Al/Cu magnetic pulse welding interface is systematically investigated using experimental characterizations and numerical simulations. A Coupled electromagnetic-mechanical simulation is proposed to compute the impact velocity and impact angle along the entire interface. This model allows to further understand the formation mechanism of various interface characteristics during MPW. The results revealed that the impact velocity gradually decreases in conjunction with the gradual increase of the impact angle. These simulations elucidate the experimentally observed successive interface morphologies, i.e., the unwelded zone, vortex zone, intermediate (IM) layers and wavy interf…
Hard material small-batch industrial machining robot
2018
Abstract Hard materials can be cost effectively machined with standard industrial robots by enhancing current state-of-the-art technologies. It is demonstrated that even hard metals with specific robotics-optimised novel hard-metal tools can be machined by standard industrial robots with an improved position-control approach and enhanced compliance-control functions. It also shows that the novel strategies to compensate for elastic robot errors, based on models and advanced control, as well as the utilisation of new affordable sensors and human-machine interfaces, can considerably improve the robot performance and applicability of robots in machining tasks. In conjunction with the developme…