The Effect of the Al Addition to the Mg-Cu-Rare Earth Rapid Solidified Alloys

S. ROZEMBERG; F. AUDEBERT; M. GALANO; I. VERGARA; C.MENDIVE

Sao Carlos

Workshop; I Workshop on Metastable and Nanostructured Materials; 2001

The Mg-Cu-Y alloys are known as good glass former around the eutectic composition of Mg65Cu25Y10. In a previous work [1] we observed when Y is substituted by Mischmetal (MM: Solid Solution of Rare Earth), a good glass forming ability is obtained. These alloys have a high hardness and rupture strength but show a brittle fracture. Regarding that the amorphous structure of these alloys can be described within the heterogeneous amorphous concept [2] we substituted part of Cu concentration by Al, finding that a ductile fracture can be achieved [1]. In this work, rapidly solidified samples of Mg65AlxCu25-xMM10 (0 < x < 15 atomic %) alloys were obtained in a splat cooling device. The structure was characterised by X ray diffraction and the stability of the amorphous alloys was analysed using differential scanning calorimetry. Nanostructured samples were prepared by annealing of the rapid solidified samples. Fractographic analysis and Vickers microhardness were carried out in both, amorphous and nanostructured samples. Besides the Young modulus was determined by nanoindentation technique in the amorphous samples. The results are correlated with the chemical composition and are discussed within the heterogeneous amorphous concept. [1] F. Audebert, S. Rozenberg and M. Galano. Journal of Non-Crystalline Solids (in press) [2] F. Audebert, B. Arcondo, D. Rodríguez and H. Sirkin. Journal of Metastable and Nanocrystalline Materials 10 (2001) 155-160.