ARTICLES Phase stability and consolidation of glassy/nanostructured Al 85 Ni 9 Nd 4 Co 2 alloys L.C. Zhang a) Fachgebiet Physikalische Metallkunde, Fachbereich 11-Material- und Geowissenschaften, Technische Universität Darmstadt, D-64287 Darmstadt, Germany; and Institut für Komplexe Materialien, IFW Dresden, D-01171 Dresden, Germany M. Calin Fachgebiet Physikalische Metallkunde, Fachbereich 11-Material- und Geowissenschaften, Technische Universität Darmstadt, D-64287 Darmstadt, Germany; and Materials Science and Engineering Faculty, University “Politehnica” of Bucharest, R-060032 Bucharest, Romania M. Branzei Materials Science and Engineering Faculty, University “Politehnica” of Bucharest, R-060032 Bucharest, Romania L. Schultz Institut für Metallische Werkstoffe, IFW Dresden, D-01171 Dresden, Germany J. Eckert b) Fachgebiet Physikalische Metallkunde, Fachbereich 11-Material- und Geowissenschaften, Technische Universität Darmstadt, D-64287 Darmstadt, Germany; and Institut für Komplexe Materialien, IFW Dresden, D-01171 Dresden, Germany (Received 3 June 2006; accepted 2 August 2006) Al 85 Ni 9 Nd 4 Co 2 metallic glass/nanostructured ribbons and powders were used as starting materials for producing bulk amorphous/nanostructured Al-based alloys. Glassy ribbons were obtained by melt spinning at wheel surface velocities ranging from 5 to 37 m/s. The amorphous ribbons exhibited a supercooled liquid region of ∼20 K, a reduced glass transition temperature of ∼0.47 and  ∼ 0.328. Mechanical alloying of the elemental powder mixture did not lead to amorphization. However, amorphous powders obtained by milling the glassy ribbons for 9 h exhibited a thermal stability similar to the initial ribbons. Isothermal differential scanning calorimetry measurements were used to determine the consolidation parameters of the glassy powders. Consolidation at 513 K by uniaxial hot pressing and hot extrusion indicated that the former method leads to bulk glassy samples, whereas the latter one yields nanostructured -Al/glassy matrix composites. I. INTRODUCTION The development of lightweight alloys is of great im- portance for meeting new requirements in various fields, i.e., for transportation systems and energy consumption. In this context, aluminum- and titanium-based alloys have achieved major importance for advanced structural applications due to their high specific strength combined with good corrosion resistance. 1,2 On the other hand, bulk metallic glasses (BMGs) have potential for applica- tions as new high-strength structural materials due to their excellent mechanical properties such as high elastic modulus and strength in comparison with their corre- sponding crystalline counterparts. 3,4 The achievement of BMG formation 3,4 and new types of marginal glass- forming systems such as Al-TM-RE alloys (TM  tran- sition metal, RE  rare-earth metal) 5–9 has extended the understanding of some of the basic factors underlying glass formation. A remarkable characteristic of these aluminum-based alloy systems is that the alloys contain >85 at.% of the base component and do not have a deep eutectic, which has been a common guideline for easy glass formation. 7 The favored compositions for glass for- mation in Al-TM-RE alloy systems have melting tem- peratures higher than that of the pure aluminum. 8,9 In- stead of a deep eutectic, it appears that a multicomponent combination of constituents with large atomic size dif- ferences (i.e., >12%) 4,10 and a negative heat of mixing 4 are key factors favoring glass formation. For amorphous Al-alloys, glass formation is favored for multicomponent a) Address all correspondence to this author. e-mail address: lczhangimr@gmail.com and l.zhang@ifw- dresden.de b) This author was an editor of this journal during the review and decision stage. For the JMR policy on review and publication of manuscripts authored by editors, please refer to http://www. mrs.org/jmr_policy. DOI: 10.1557/JMR.2007.0156 J. Mater. Res., Vol. 22, No. 5, May 2007 © 2007 Materials Research Society 1145