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vol.15 issue5Processing and microstructural characterization of a Ti-Cr-Nb alloy synthesized by high-energy ball-millingStudy of the Al-Si-X system by different cooling rates and heat treatment author indexsubject indexarticles search
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Materials Research

Print version ISSN 1516-1439

Abstract

TRIVENO RIOS, Carlos et al. Stability of an amorphous alloy of the Mm-Al-Ni-Cu system. Mat. Res. [online]. 2012, vol.15, n.5, pp.757-762.  Epub Aug 30, 2012. ISSN 1516-1439.

An investigation was made of the stability of melt-spun ribbons of Mm55Al25Ni10Cu10 (Mm = Mischmetal) amorphous alloy. The structural transformations that occurred during heating were studied using a combination of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Crystallization took place through a multi-stage process. The first stage of transformation corresponded to the formation of a metastable phase followed by cfc-Al precipitation, while in the second stage, exothermic transformations led to the formation of complex and unidentified Mm(Cu, Ni) and MmAl(Cu, Ni) phases. The transformation curves recorded from isothermal treatments at 226 °C and 232 °C indicated that crystallization occurred through nucleation and growth, with diffusion-controlled growth occurring in the first crystallization stage. The supercooled liquid region, ∆Tx, at 40 K/min was ~80 K. This value was obtained by the substitution of Mm (=Ce + La + Nd + Pr) for La or Ce, saving chemical element-related costs.

Keywords : mischmetal based glass alloys; crystallization; thermal stability.

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