چكيده به لاتين
AZ91 Alloy is one of the magnesium alloys which is more cost-effective compared to the other alloys of this category of materials. This alloy is used in aerospace and vehicle manufacturing industries and shows appropriate castability.
Since casting of thin sections is done properly using magnesium alloys, in the current project, investigation of fluidity or melt progression in mold in the absence of protective atmosphere is intended.
Although magnesium alloys have unique properties, they show very oxidation resistance. Therefore in the absence of the protective atmosphere, the melt quality diminishes severely.
In current study, by addition of calcium oxidation resistance of this category of materials has been significantly increased. Investigation of this effect is done using oxidation resistance measurement tests in molten state, microstructure analysis and X-ray diffraction pattern.
According to the results, adding 2 wt.% calcium to AZ91 alloy melt has been considered the optimum amount and this amount of calcium has well proved the oxidation resistance at 700oC for storage time of 40 minutes. Furthermore addition of this amount of calcium, increased the measured fluidity in spiral mold at casting temperature of 690-700oC from 10 cm to 34 cm.
Keywords: Magnesium alloys, oxidation resistance, fluidity, protective atmosphere
