Search results for "ALLOYS"
showing 10 items of 1689 documents
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 …
Linear friction welding of dissimilar AA6082 and AA2011 aluminum alloys: microstructural characterization and design guidelines
2015
This paper presents the results of an experimental and numerical campaign on Linear Friction Welding of dissimilar AA2011-T8 and AA6082-T6 aluminum alloys. Experimental tests were carried out with constant oscillation amplitude and process time. Varying oscillation frequency, interface pressure, specimen geometry and mutual position were used. Grain size measurements, HV tests and EDX analysis were considered to characterize the microstructure of the joints as a function of the input process parameters. A thermal numerical model was utilized to predict the temperature profiles in the joints during the process. The obtained results allowed the identification of four weld categories: sound jo…
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…
A flexible robotic cell for in-process inspection of multi-pass welds
2020
Welds are currently only inspected after all the passes are complete and after allowing sufficient time for any hydrogen cracking to develop, typically over several days. Any defects introduced between passes are therefore unreported until fully buried, greatly complicating rework and also delaying early corrections to the weld process parameters. In-process inspection can provide early intervention but involves many challenges, including operation at high temperatures with significant gradients affecting acoustic velocities and, hence, beam directions. Reflections from the incomplete parts of the weld would also be flagged as lack-of-fusion defects, requiring the region of interest (ROI) t…
Incidence of Stent Thrombosis after Endovascular Treatment of Iliofemoral or Caval Veins in Patients with the Postthrombotic Syndrome.
2019
Abstract Background Patients with postthrombotic syndrome (PTS) treated with stents are at risk of stent thrombosis (ST). The incidence of ST in the presence and absence of anticoagulation therapy (AT) is unknown. Risk factors are not well understood. Patients and Methods From the prospective Swiss Venous Stent registry, we conducted a subgroup analysis of 136 consecutive patients with PTS. Incidence of ST was estimated from duplex ultrasound or venography, and reported for the time on and off AT. Baseline, procedural, and follow-up data were evaluated to identify factors associated with ST. Results Median follow-up was 20 (interquartile range [IQR] 9–40) months. AT was stopped in 43 (32%) …
Binding and neurotoxicity mitigation of toxic tau oligomers by synthetic heparin like oligosaccharides.
2018
Well-defined heparin like oligosaccharides up to decasaccharides were synthesized. It was discovered for the first time that heparin oligosaccharides, as short as tetrasaccharides, can bind with the most toxic tau species, i.e., tau oligomers with nM KD. The binding significantly reduced the cellular uptake of toxic tau oligomers and protected the cells from tau oligomer induced cytotoxicity.
Selective Cytotoxic Activity of Prodigiosin@halloysite Nanoformulation
2020
Prodigiosin, a bioactive secondary metabolite produced by Serratia marcescens, is an effective proapoptotic agent against various cancer cell lines, with little or no toxicity toward normal cells. The hydrophobicity of prodigiosin limits its use for medical and biotechnological applications, these limitations, however, can be overcome by using nanoscale drug carriers, resulting in promising formulations for target delivery systems with great potential for anticancer therapy. Here we report on prodigiosin-loaded halloysite-based nanoformulation and its effects on viability of malignant and non-malignant cells. We have found that prodigiosin-loaded halloysite nanotubes inhibit human epithelia…
Conf-VLKA: A structure-based revisitation of the Virtual Lock-and-key Approach
2016
In a previous work, we developed the in house Virtual Lock-and-Key Approach (VLKA) in order to evaluate target assignment starting from molecular descriptors calculated on known inhibitors used as an information source. This protocol was able to predict the correct biological target for the whole dataset with a good degree of reliability (80%), and proved experimentally, which was useful for the target fishing of unknown compounds. In this paper, we tried to remodel the previous in house developed VLKA in a more sophisticated one in order to evaluate the influence of 3D conformation of ligands on the accuracy of the prediction. We applied the same previous algorithm of scoring and ranking b…