Comportamiento a ‘creep’ de la aleación AZ-91 e influencia del compuesto intermetálico Al 12 Mg 17

Zusammenfassung

Magnesium alloys, due to the excellent relationship between their mechanical properties and weight, have aroused great interest, mainly in the automotive sector. The AZ91 alloy is wi- dely used, but their mechanical properties are limited. In this paper we study the improvement of these characteristics and the difficulty to withstand creep or creep above 150 ºC. On the other hand, the conclusions obtained in this article, show that the intermetallic compound Al 12 Mg17 formed by this alloy, far from benefiting it, significantly damages its mecha- nical properties. In order to improve these properties, it has been found that certain amounts of antimony (0.5%) and si- licon (0.5%) in AZ-91 alloy improve the creep tests at 150 ºC of this alloy. This cannot be guaranteed above 200 ºC. It has been shown that the working temperature of the AZ-91 alloy should not exceed 150 ºC to maintain acceptable mechanical properties.