The effects of annular electromagnetic stirring parameters on microstructure evolution of rheocast AZ91 magnesium alloy

• Main Authors: N. Farzam Mehr, H. Aashuri
• Format: Article
• Language: English
• Published: Elsevier 2019-04-01
• Series: Journal of Materials Research and Technology
• Online Access: http://www.sciencedirect.com/science/article/pii/S2238785418312420

In the present study, an annular electromagnetic stirrer was used to fabricate the semi-solid slurry of AZ91 magnesium alloy under various conditions of electromagnetic intensities and times. The fabricated semi-solid slurry was injected into a step-die cavity, using a hydraulic jack with ram speed of 1 m/s. The effects of electromagnetic intensity, stirring time and step thicknesses on the microstructure evolution, shape factor, globules equivalent diameter, solid fraction and microhardness of samples were investigated. The experimental results showed that obtained optimal parameters of electromagnetic stirring were 55 (A) stirring current and 30 (s) stirring time. In this conditions, the value of shape factor, was ∼0.85. By increasing the thickness of the steps, the shape factor and micro-hardness value was decreased, whereas, the equivalent diameter of globules and solid fraction were increased. Keywords: AZ91 magnesium alloy, Semi-solid process, Electromagnetic stirring, Rheocasting, Image analysis, Micro-hardness