The influence of high intensity ultrasound (US) propagating through a steel mold on the microstructure and mechanical properties of die-cast AlSi9Cu3, for different levels of electric power and at different distances to the waveguide/mold interface. The influence of those parameters on the morphology of -Al and eutectic Si and on the volume of porosity were investigated and characterized. The morphological ch...
Low density, high strength to corrosion and specific strength to weight ratio are properties that made aluminum alloys excellent materials for transportation industry. A promising way to develop ultra-high strength aluminum alloys is achieved by the addition of metallic elements with low solubility in aluminum, promoting the Al3X (X = Sc) nanoparticles formation. Moreover, Al alloys have applications in the aer...
The grain refinement effect and the ageing behaviour of Al–0.5 wt.% Sc, Al–0.7 wt.% Sc, and Al–1 wt.% Sc alloys are studied on the basis of optic microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) observations and hardness measurements. In Al–Sc alloys the higher grain refinement is observed for Sc contents greater than 0.5 wt.% accompanied by a notorious morphology modification, from ...
Denervation of the colon is protective against the colon cancer; however, the mechanisms involved are unknown. We tested the hypothesis that the denervated colonic mucosa could be less responsive to the action of the chemical carcinogen dimethylhydrazine (DMH). Three groups of 32 male Wistar rats were treated as follows: group 1 (G1) had the colon denervated with 0.3 mL 1.5 mM benzyldimethyltetradecylammonium (...
The heat treatment of γ-TiAl alloy (Ti-47Al-2Cr-2Nb (at.%)) diffusion brazed joints was investigated. Joining was performed using a Ti/Ni/Ti clad-laminated braze alloy foil at 1050 and 1150ºC with a dwell time of 10 minutes. The joints were subsequently heat treated at 1250 and 1350ºC for 240 and 30 minutes, respectively. The microstructure and the chemical composition of the interfaces were analysed by scannin...
Ti-47Al-2Cr-2Nb was joined by diffusion brazing using a Ti-Ni clad-laminated filler alloy. Brazing was performed in the temperature range of 1000 to 1200ºC for 10 min. The microstructure and the chemical composition of the interfaces were studied by scanning electron microscopy (SEM) and by energy dispersive X-ray scans (EDS), respectively. The reaction between the gamma-TiAl alloy and the liquid produced inter...
The joining of Ti-47Al-2Cr-2Nb using Ti-15Cu-15Ni (wt.%) as braze alloy was investigated. Experiments were conducted at 980 and 1000ºC for 10 min. The microstructure and the chemical composition of the interfaces were studied by scanning electron microscopy (SEM) and by energy dispersive X-ray spectroscopy (EDS), respectively. For both processing conditions the reaction between the gamma-TiAl alloy and the braz...
The joining of Ti-47Al-2Cr-2Nb (at.%) by diffusion brazing at 1000, 1050 and 1100ºC for 10 min, using a Ti-15Cu-15Ni (wt.%) braze alloy was investigated. The icrostructure and the chemical composition of the interfaces were studied by scanning electron microscopy (SEM) and by energy dispersive X-ray scans (EDS), respectively. The reaction between the gamma-TiAl alloy and the braze alloy led to the formation of ...
The joining of a gamma-TiAl alloy using Incusil-ABA as filler metal was investigated. Bonding was performed in a high vacuum furnace at 750 ºC for 10 min. The interfacial microstructure was analysed by SEM and its composition was investigated by EDS. An intense diffusion of Ti and Al to the interface and a strong reaction between the braze alloy and the base metal were observed. The interface could be divided i...
Macor® machinable glass-ceramic and commercially pure (cp.) titanium were joined by active metal brazing, using a 64Ag–34.5Cu–1.5Ti (wt.%) filler alloy. The influence of the brazing temperature and holding stage on the microstructure and hardness profile of the interface, as well as on the shear strength of the joint, were assessed. Brazing was performed in a high vacuum furnace at 850, 890 and 930°C for 10 an...
Financiadores do RCAAP | |||||||
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |