Quantitative microstructure study of melt-spun Mg 65 Cu 25 Y 10

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Quantitative microstructure study of melt‑spun ­Mg65Cu25Y10 Alexander Katz‑Demyanetz1 · Menachem Bamberger2 · Michael Regev3  Received: 28 May 2020 / Accepted: 16 September 2020 © Springer Nature Switzerland AG 2020

Abstract Mg65Cu25Y10 ribbons were produced by melt spinning. XRD, DSC, HRSEM and HRTEM were used to investigate their microstructure in its as-cast condition as well as after 3- and 6-minute exposures to 100 °C, 120 °C, 150 °C, 200 °C and 300 °C. XRD and DSC studies showed that the as-cast material had an amorphous character; the HRTEM investigation revealed that although the as-cast ­Mg65Cu25Y10 is known to be one of the best glass formers, it is nano-crystalline rather than amorphous. The fraction of the crystalline phase after each treatment was calculated by means of quantitative analysis that took into account the degree of crystallinity of the as-cast material as revealed by HRTEM. The current study showed that quantitative analysis may lead to serious errors when relying on the absence of crystalline peaks in the XRD spectrum as if the material is completely amorphous. Moreover, it seems that HRTEM examination is essential for carrying out quantitative XRD and DSC analyses.

*  Michael Regev, [email protected]; Alexander Katz‑Demyanetz, [email protected]; Menachem Bamberger, mtrbam@ technion.ac.il | 1Foundry Laboratory, Israel Institute of Metals, Technion – Israel Institute of Technology, Haifa, Israel. 2Department of Materials Science and Engineering, Technion – Institute of Technology, Haifa, Israel. 3Mechanical Engineering Department, ORT Braude College of Engineering, P.O.B. 78, Karmiel, Israel. SN Applied Sciences

(2020) 2:1811

| https://doi.org/10.1007/s42452-020-03522-3

Vol.:(0123456789)

Research Article

SN Applied Sciences

(2020) 2:1811

| https://doi.org/10.1007/s42452-020-03522-3

Graphic abstract 

Keywords Mg65Cu25Y10 · Melt spinning · Metallic glass · HRTEM · XRD · DSC

1 Introduction Magnesium alloys are characterized by good physical properties: they exhibit high strength, are lightweight, and have good damping absorption and good thermal and electrical conductivity. Amorphous magnesium alloys, moreover, exhibit higher strength, hardness, and a large elastic domain in addition to having excellent corrosion resistance. Among the various existing magnesium alloys, the Mg–Cu–Y system is known to be one of the best glass formers. The M ­ g65Cu25Y10 was reported in Vol:.(1234567890)

early publications of Inoue et al. [1–3], who pointed at Cu content of 25 at. % and Y content of 10 at. % as optimal for high Glass Forming Ability (GFA) so that BMG rods with a diameter of 4 mm could be produced by copper mold casting. This high GFA is due to the lowest critical cooling rate and ( the)largest temperature span of the supercooled region ΔTx in the Mg–Cu–Y system, both achieved with the ­Mg65Cu25Y10 composition and equal 93 K/s and 60 °C, respectively. The temperature span of the supercooled region is defined as follows:

SN Applied Sciences

(2020) 2:1811

) ( ΔTx =