An Automated Visual Inspection System for the Classification of the Phases of Ti-6Al-4V Titanium Alloy

Metallography is the science of studying the physical properties of metal microstructures, by means of microscopes. While traditional approaches involve the direct observation of the acquired images by human experts, Com-puter Vision techniques may help experts in the analysis of the inspected mate-rials. In this paper we present an automated system to classify the phases of a Titanium alloy, Ti-6Al-4V. Our system has been tested to analyze the final products of a Friction Stir Welding process, to study the states of the micro-structures of the welded material

A comparative kinetic study of Pb and Pb-Sb electrodes in sulfuric acid solutions

The electrochemical responses of Pb and Pb-3.4% Sb electrodes in 5 M H2SO4 were examined combining potential sweep and potential step techniques. The presence of antimony prevents the complete blockage of the electrode active surface by PbSO4 crystals during electro-oxidation, changing the composition and structure of the passive layer. The electro-oxidation of Sb was interpreted in terms of an adsorption-dissolution mechanism where in the rate-determining step one electron is transferred. The growth kinetics of the PbO inner layer was also studied. On the Pb-Sb electrode, the growth rate of PbO decreases because of a change in the transport mechanism of ions through the anodic layer

Propriedades mecânicas e resistência à corrosão da liga Ti-4Al-4V obtida da reciclagem da liga Ti-6Al-4V

The present work aimed to study the transformation from as-cast structure of the Ti4Al-4V alloy, as a result of the Ti-6Al-4V recycling, after some rapid heat treatments based on martensitic reactions. The effects on mechanical properties were evaluated by Vickers hardness measurements, Charpy and monotonic tensile tests. The corrosion strength was tested by immersion during 4 months in artificial physiological solutions, to evaluate its possible use as a biomaterial. The data pointed to: a) a reduction on corrosion strength for quenching above beta transus; b) significant increasing on hardness and mechanical strength; c) a maintenance of impact toughness; d) the corrosion strength for immersion in a NaCl 1%+ NaF 0,1% (m/m) was lower in all conditions, specially for those including heating to 900 °C

Propriedades mecânicas e resistência à corrosão da liga Ti-4Al-4V obtida da reciclagem da liga Ti-6Al-4V

The present work aimed to study the transformation from as-cast structure of the Ti4Al-4V alloy, as a result of the Ti-6Al-4V recycling, after some rapid heat treatments based on martensitic reactions. The effects on mechanical properties were evaluated by Vickers hardness measurements, Charpy and monotonic tensile tests. The corrosion strength was tested by immersion during 4 months in artificial physiological solutions, to evaluate its possible use as a biomaterial. The data pointed to: a) a reduction on corrosion strength for quenching above beta transus; b) significant increasing on hardness and mechanical strength; c) a maintenance of impact toughness; d) the corrosion strength for immersion in a NaCl 1%+ NaF 0,1% (m/m) was lower in all conditions, specially for those including heating to 900 °C