Abstract
In this article, the effect of flux on melting behavior and surface properties of investment casting of AZ91D magnesium alloy using in-situ melting technique was investigated. AZ91D granules together with different flux percentages and applications were charged into shell investment molds and heated at 750°C in argon-protected environment in order to produce AZ91D investment casting. Surface of castings and the occurred mold-metal interfacial reaction were analyzed. It was found that the application of flux together with the granules is essential to produce a solid investment cast alloy. The results showed that the use of flux mixed with the granules and sprinkled on the top of the granules as a layer produced higher surface quality casting. Microscopic examinations revealed that flux developed a barrier layer which reduced mold-metal reaction and contributed to an improved approach in AZ91D magnesium alloys investment casting process.