43 documents found, page 1 of 5
Polyarthritis due to metastatic calcinosis in a patient with new WT1 gene mutat...
Martins, F. Rajão; Gonçalves, Francisco; Guedes, A.; Sequeira, G.; Ribeiro, C.Metastatic calcinosis is an uncommon condition characterized by diffuse soft tissue calcification, which may occur with advanced chronic kidney disease (CKD), typically in those undergoing kidney replacement therapy (1, 2). Deposits usually appear around large joints such as the elbow, hip, and shoulder. Periarticular deposits may lead to arthralgia, reduced joint mobility, and neurovascular symptoms. Sustained...
Microstructure, mechanical properties and corrosion behaviour of Ti6Al4V/Al2O3 ...
Alves, Alexandra Manuela Vieira Cruz Pinto; Pinto, A. M. P.; Simões, S.; Guedes, A.Ti6Al4V and Al2O3 were successfully vacuum brazed at 980 °C using TiCuNi filler foil. The microstructure and the chemical composition of the interface were analysed by SEM (scanning electron microscopy) and EDS (energy dispersive spectros- copy), respectively. The hardness profile across the interface and the mechanical strength of joints were assessed by Vickers microhardness tests and shear tests, respectivel...
O projecto EXCITE
Caldeira, Rita; Gonçalves, M. A.; Guimarães, Fernanda; Rodrigues, P. C. R.; Walter, S.; Guedes, A.; ter Maat, G.ABSTRACT: The EXCITE (Electron and X-ray microscopy Community for structural and chemical Imaging Techniques for Earth materials) project, unites leading European facilities for electron and X-ray microscopy of earth materials. This project is mainly focused in providing access to existing high-end facilities in the field of earth and material sciences and, by this, enabling knowledge and experience exchanging ...
Joining of zirconia to Ti6Al4V using Ag-Cu sputter-coated Ti brazing filler
Simões, Sónia; Emadinia, Omid; Tavares, C. J.; Guedes, A.The joining of zirconia (ZrO<sub>2</sub>) to Ti6Al4V using Ag-Cu sputter-coated Ti brazing filler foil was investigated. Brazing experiments were performed at 900, 950, and 980 °C for 30 min under vacuum. The microstructural features of the brazed interfaces were evaluated by optical microscopy (OM) and by scanning electron microscopy (SEM). The chemical composition of the brazed interfaces was analyzed by ener...
Corrosion and tribocorrosion behaviour of Ti-B4C composites processed by conven...
Sousa, L.; Alves, Alexandra Manuela Vieira Cruz Pinto; Guedes, A.; Toptan, FatihIn this work, low volume reinforcement ex-situ Ti-B4C composites were produced using two different routes: conventional powder metallurgy (PM) and hot-pressing (HP). The effect of reinforcement phases and processing method on corrosion and tribocorrosion behaviour were studied. Composites processed by PM lost the typical passive behaviour of Ti matrix, while composites processed by HP presented similar behaviou...
Electrochemical response of Ti joints vacuum brazed with TiCuNi, AgCu, and Ag f...
Marinho, C.; Toptan, Fatih; Guedes, A.; Alves, Alexandra Manuela Vieira Cruz PintoThe properties of the joints are dictated by the nature, distribution, and morphology of the phases formed at the interface. The mechanical properties of brazed joints are well documented in the literature, contrarily to their electrochemical behaviour. Thus, the main objective of this study was to understand the influence of the phases formed at the interface on the corrosion behaviour of commercially pure Ti ...
Joining alumina to titanium alloys using Ag-Cu sputter-coated Ti brazing filler
Emadinia, Omid; Guedes, A.; Tavares, C. J.; Simões, SóniaThe joining of alumina (Al<sub>2</sub>O<sub>3</sub>) to γ-TiAl and Ti6Al4V alloys, using Ag-Cu sputter-coated Ti brazing filler foil, was investigated. Brazing experiments were performed at 980 °C for 30 min in vacuum. The microstructure and chemical composition of the brazed interfaces were analyzed by scanning electron microscopy and by energy dispersive X-ray spectroscopy, respectively. A microstructural cha...
Joining of TiAl alloy using novel Ag-Cu sputtered coated Ti brazing filler
Simões, Sónia; Soares, Ana; Tavares, C. J.; Guedes, A.The aim of this study is to evaluate the potential use of titanium foil coated with sputtered silver and copper films as a novel brazing filler for joining TiAl alloys. For this purpose, a detailed microstructural characterization of the resulting brazing interfaces was carried out. The development of brazing fillers that allow the joining of TiAl alloys without compromising the service temperature is a fruitfu...
Corrosion and tribocorrosion behavior of Ti-B4C composites joined with TiCuNi b...
Sousa, J. M.; Alves, Alexandra Manuela Vieira Cruz Pinto; Toptan, Fatih; Ariza, E.; Guedes, A.Corrosion behavior of joined Ti-B4C composites was evaluated in 9 g/L NaCl solution using cyclic polarization and electrochemical impedance spectroscopy. Tribocorrosion behavior was investigated by sliding against an alumina ball under open-circuit potential and potentiodynamic polarization. The results showed that joining did not negatively affect the corrosion behavior of the composites. Regarding tribocorros...
Joining of γ-TiAl alloy to Ni-Based superalloy using Ag-Cu sputtered coated Ti ...
Simões, Sónia; Tavares, C. J.; Guedes, A.Joining γ-TiAl alloy to Ni-based superalloy Hastelloy using Ag-Cu sputtered coated Ti foil as brazing filler was investigated in this study. Brazing experiments were performed at 900, 950, and 980 °C with a dwelling stage of 10 min in vacuum. The microstructure and the chemical composition of the resulting interfaces were analyzed by scanning electron microscopy (SEM) and by energy dispersive X-ray spectroscopy...