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Synthesis and characterization of Ti₃SiC₂/Mg and Cr₂AlC/Mg composites
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Synthesis and characterization of Ti₃SiC₂/Mg and Cr₂AlC/Mg composites

Matthew Jared Nelson
Master of Science (M.S.), Drexel University
Jun 2014
DOI:
https://doi.org/10.17918/etd-4486
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Abstract

Alloys--Mechanical properties Magnesium--Metallurgy Materials Science
High strength, light-weight materials are in high demand in many applications; especially aerospace and the military. The focus of this work is to report on the fabrication and characterization of Ti₃SiC₂ and Cr₂AlC MAX phase reinforced Mg and Mg-alloy metal matrix composites synthesized by pressureless melt infiltration. Pure Mg and Al-containing Mg-alloys (AZ31, AZ61 & AZ91) with varying Al content were matrices with loadings of ~ 45±1 vol. %. The resulting microstructures and mechanical properties were characterized by X-ray diffraction, scanning electron microscopy (SEM), and compressive stress testing. SEM revealed kinked, delaminated, and elongated Ti₃SiC₂ grain, and non-deformed, rounded Cr₂AlC grain morphologies. Like in the Ti₂AlC/Mg composite system, increasing the Al wt. % content in the matrix enhanced the mechanical properties of the Ti₃SiC₂ composite system, but had a deleterious effect on the properties of the Cr₂AlC composite system. At 1.9±0.1 GPa, 346±4 MPa and 617±10 MPa, the Vickers hardness, yield strength and ultimate compressive strength, respectively, of the Ti₃SiC₂/AZ91 composite were the highest in this study. All composites fabricated in this work exhibited fully and spontaneously reversible hysteresis loops due to the back and forth motion of dislocations. A small change in reinforcement volume fraction was found to affect the measured mechanical properties.

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