| Popis: |
Abstract In this work, the effect of the increase in the concentration of aluminium (Al) on the microstructure and the hardness of bronze to aluminium was studied using optical emission spectrometry, scanning electron microscopy, dispersion spectroscopy techniques of energy, conventional optical microscopy and hardness tests. Alloys with three concentrations by weight of aluminium (Cu-4.5 wt.% Al, Cu-7 wt.% Al and Cu-10 wt.% Al) were studied, with the chemical parameters established in the (ASTM B-824), were manufactured and cast in a permanent mold according to the standard (ASTM B-208), to determine the influence of the chemical concentration of aluminium the response surface methodology was used. It was observed that bronzes with a content of 4.5 wt.% Al and 7 wt.% Al, remain with a constant microstructure of phase α, and bronzes of 10 wt.% Al, undergo a change from monophasic to biphasic microstructure (α + β) evidencing the appearance of a martensitic microstructure similar to steels providing a better behaviour to resistance to indentation. It is concluded that the increase in the concentration of Al, in the Cu-Al alloy, presents a microstructural change, and the appearance of a β and β 'phase generates a better property in hardness, the hardness has a behaviour k proportional to the aluminium concentration obtaining 53 Brinell value for an increase in the concentration of 5.5 wt.% Al. |
