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Title
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Zr Addition and Milling Time Impact
on the Microstructure and Phase Analysis of New
Mg-3Zn-xZr (x = 0, 0.5, 1, 2, and 3) Alloys Synthesized
with High-Energy Ball Milling and the Subsequent
Sintering
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Abstract
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In this study, Mg-3Zn-xZr (x = 0 ,0.5, 1, 2, and 3) alloy powder was obtained by using high-energy ball
milling (10-h milling). The obtained powders were compacted in a way that they had the cylindrical samples
with a 10 mm diameter and the pressure of 400 MPa and sintered. Scanning electron microscopy (SEM),
energy-dispersive x-ray spectrometer (EDS), and x-ray diffraction (XRD) were then applied for the purpose
of investigating the Zr content and milling time effect on the morphology evolution of Mg-3Zn-xZr milled
powders as well as the microstructural qualities of the Mg-3Zn-xZr sintered samples. The considered lattice
properties of the composite powders were subjected to thorough characterization through the Rietveld and
Williamson-Hall methods. In addition, the relative densities as well as hardness values of the Mg-3Zn-xZr
sintered samples were examined. The hardness of Mg-Zn-xZr powder enhanced with milling time and
increased to 101.35 HV by adding 3 wt.% Zr. The obtained results confirmed that the addition of Zr led to
some significant changes in the crystallite parameters as well as milling behavior of Mg-3Zn. The results
also indicated that with the rise of the Zr content, finer and equiaxial nanocomposite powders were
obtained after 10 hours of milling. Further, the XRD analyses provided the indication that Mg diffraction
peaks were broadened, whereas their intensities decreased with increasing Zr. Also, the XRD results
displayed that the Mg solid solution was wholly developed, and the milled powders were single phase, and
no secondary phase was observed after milling, while the secondary phases were formed after sintering in
higher amounts of Zr (> 2 wt.%). In addition, the obtained results provided the indication that the relative
density and hardness values related to the Mg-3Zn-xZr sintered samples showed improvement with the
increase in the Zr content.
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