The Microstructure and Tensile Properties of a Newly Developed Mg–Al/Mg3Sb2 In Situ Composite in As-Cast and Extruded Conditions

Autor: A. Montajabnia, Masoud Emamy, B. Pourbahari
Rok vydání: 2018
Předmět:
Zdroj: Metals and Materials International. 24:1099-1111
ISSN: 2005-4149
1598-9623
DOI: 10.1007/s12540-018-0124-5
Popis: The microstructures and tensile properties of Mg–x wt%Al–y wt%Sb alloys have been studied where x/y ratio was 1 and Sb(Al) contents were 5, 10, 15 and 20 wt%, respectively. The results indicated that by increasing Sb(Al) content, not only the crystals of primary Mg3Sb2 alter from small flake-like particles to polygonal or needle-like morphology, but also the eutectic structure changes from semi-continuous network in Mg–5Al–5Sb to continuous network in Mg–20Sb–20Al alloy. The results obtained from thermal analysis revealed different peaks related to the formation of Mg3Sb2 as primary phase and eutectic structure containing Mg17Al12 + Al3Mg2 intermetallic phases. Further results also revealed that Sb(Al) additions change the solidification performance of the material by depressing the Mg3Sb2 nucleation temperature, reducing solidification range and widening eutectic area. Tensile testing results showed that with the increase in Sb (Al) content, ultimate tensile strength (UTS) and elongation values of the alloys are decreased in as-cast condition. But, significant improvement in the UTS and elongation values of the extruded specimens was attributed to the severe fragmentation of intermetallic phases and well distributed fine particles in the matrix which provided proper obstacles for dislocation motion. It was interesting to note that the fracture behavior of intermetallic particles was found to be different, while Mg3Sb2 was ductile, intermetallic compounds in eutectic regions were brittle.
Databáze: OpenAIRE
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