The Effects of Grain Refinement and Rare Earth Intermetallics on Mechanical Properties of As-Cast and Wrought Magnesium Alloys

Journal Article · Thu Mar 15 04:00:00 EDT 2018 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-018-3238-5· OSTI ID:22858010

Pourbahari, Bita; Mirzadeh, Hamed; Emamy, Massoud ^[1]

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1. University of Tehran, School of Metallurgy and Materials Engineering, College of Engineering (Iran, Islamic Republic of)

The effects of rare earth intermetallics and grain refinement by alloying and hot extrusion on the mechanical properties of Mg-Gd-Al-Zn alloys have been studied to elucidate some useful ways to enhance the mechanical properties of magnesium alloys. It was revealed that aluminum as an alloying element is a much better grain refining agent compared with gadolinium, but the simultaneous presence of Al and Gd can refine the as-cast grain size more efficiently. The presence of fine and widely dispersed rare earth intermetallics was found to be favorable to achieve finer recrystallized grains during hot deformation by extrusion. The presence of coarse dendritic structure in the GZ61 alloy, grain boundary eutectic containing Mg{sub 17}Al{sub 12} phase in the AZ61 alloy, and rare earth intermetallics with unfavorable morphology in the Mg-4Gd-2Al-1Zn alloy was found to be detrimental to mechanical properties of the alloy in the as-cast condition. As a result, the microstructural refinement induced by hot extrusion process resulted in a significant enhancement in strength and ductility of the alloys. The presence of intermetallic compounds in the extruded Mg-4Gd-2Al-1Zn and Mg-2Gd-4Al-1Zn alloys deteriorated tensile properties, which was related to the fact that such intermetallic compounds act as stress risers and microvoid initiation sites.

• OSTI ID: 22858010
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 3 Vol. 27; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM COMPOUNDS
COMPARATIVE EVALUATIONS
DEFORMATION
DENDRITES
DUCTILITY
EUTECTICS
EXTRUSION
GADOLINIUM COMPOUNDS
GRAIN BOUNDARIES
GRAIN REFINEMENT
GRAIN SIZE
INTERMETALLIC COMPOUNDS
MAGNESIUM ALLOYS
MAGNESIUM COMPOUNDS
QUATERNARY ALLOY SYSTEMS
REFINING
STRESSES
ZINC COMPOUNDS