Abstract

Several commercial alloys use silicon (Si) to improve titanium (Ti) resistance to creep and oxidation at high temperatures and to improve Ti corrosion resistance in acid media. According to the Ti-Si phase diagram, reported stable solid phases in the Ti-rich region are beta-Ti,alpha-Ti, Ti3Si, and Ti5Si3. Nevertheless, very few works in the literature discuss Ti3Si intermetallic production. As such, this work studied the possibility of obtaining an alpha-Ti-Ti3Si alloy by hot pressing alpha-Ti supersaturated solid solution powders obtained by mechanical alloying. The consolidation of milled powders was performed using uniaxial hot press equipment. Structural and morphological evolutions during the sintering process were investigated by X-ray diffraction and scanning electron microscopy. Electrochemical behaviors of sintered samples were evaluated by open circuit potential and linear sweep voltammetry. Results show a fine and uniform Ti3Si alloy distribution in the alpha-Ti matrix produced by the proposed powder metallurgy route. The sintered samples demonstrated high micro-hardness and resistance to sulfuric acid corrosion. Additionally, Ti3Si was shown to have a significant hardening effect on the alpha-Ti matrix. Electrochemical behavior further demonstrates that a fine and homogeneous Ti3Si distribution in the alpha-Ti matrix contributes to a more stable superficial oxide layer against sulfuric acid corrosion.