Correlation between Hardness, Structure and Electrochemical Performance of an AlZnMnMg Alloy
- 1 Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Morelos, México
- 2 Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Morelos, México
- 3 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México City, México
Abstract
In this work the structural changes induced by aged treatment have shown a connection with differences of hardness and electrochemical performance. Al-base alloys have been investigated by means of Vickers hardness, X-ray diffraction, scanning electron and short-term electrochemical test. X-ray diffraction result reveals the formation of (MgZn)49Al32 phase for two conditions, the first one is when the magnesium content is upper to 5.49% in as-cast condition and the second one after the thermal treatment carried out at 450?C for 5 h. In addition, the hardness and electrochemical performance has been influenced by the presence and quantity of the (MgZn)49Al32 phase. The addition of magnesium alloying modifies the microstructure, increases the content of (MgZn)49Al32 phase and provides a localized corrosion which conduced to the breakdown of the oxide film (?-Al2O3) formed on the Al alloy surface.
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