Materials Science and Engineering A 384 (2004) 262–269 High-temperature mechanical behaviour of Cu–Ti–C, Cu–Al and Cu–Ti–Al–C alloys obtained by reaction milling Rodrigo H. Palma a,∗ , Aquiles O. Sep ´ ulveda a , Rodrigo G. Espinoza a , Alejandro P. Z´ u˜ niga b , M. Jes ´ us Di´ anez c , Jos´ e M. Criado c , M. Jes ´ us Sayagu´ es c a Departamento de Ingenier´ ıaMec´ anica, Universidad de Chile, Beauchef 850, 4 ◦ Piso, Santiago 6511261, Chile b Departamento de Ingenier´ ıaMec´ anica, Universidad de Chile, Department of Chemical Engineering and Materials Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA c Instituto de Ciencia de Materiales de Sevilla, Am´ erico Vespucio s/n, Isla de La Cartuja, Sevilla, Spain Received 15 March 2004; received in revised form 3 June 2004 Abstract The mechanical behaviour of Cu–5 vol.% Al 2 O 3 , Cu–5 vol.% TiC and Cu–2.5 vol.% TiC–2.5 vol.% Al 2 O 3 alloys (nominal compositions) prepared by reaction milling and extrusion at 1023 K was studied between 673 and 1123 K. The annealing-softening resistance and the compression resistance at elevated temperatures of these alloys increased according to the following trend: Cu–5vol.% Al 2 O 3 ; Cu–5 vol.% TiC; Cu–2.5 vol.% TiC–2.5 vol.% Al 2 O 3 . An explanation for this behaviour is given. © 2004 Elsevier B.V. All rights reserved. Keywords: Copper alloys; Creep; Dispersion-strengthening; Mechanical alloying 1. Introduction Numerous applications require microstructurally stable materials exhibiting high strength at high temperatures in combination with high electrical and/or thermal conductivity. Among these applications, one can name: (a) in the electronic industry: high-performance switches, electromotors, and heat exchangers and (b) in manufacturing industry: actively cooled components, rocket nozzles, magnetic cables and wires, and electrode tips for resistance welding [1]. Due to its high electrical/thermal conductivity, copper is a most promising metal for all these applications. Moreover, copper has the advantage of a low elastic modulus, which minimizes thermal stresses in actively cooled structures [2]. However, its strength has to be increased in order to meet the design requirements for high-temperature applications. The high-temperature resistance of metallic alloys can be increased by adding a small fraction (e.g., between 2 and ∗ Corresponding author. 5 vol.%) of ceramic dispersoids. In contrast to solid solution strengthening, the addition of elements to form insoluble par- ticles has very little effect on the electrical conductivity. On the other hand, upon adding ceramic dispersoids, the high- temperature strength of the material is mainly controlled by two mechanisms: dislocation–particle interaction, and grain boundary–particle interaction. The dislocation–particle inter- action involves climbing and detachment of the dislocation line from the particle–matrix interface, with incoherent inter- faces being the most effective ones [3]. However, in the case of grain boundary–particle interaction, coherent interfaces are more useful when preventing grain boundary sliding [4]. One of the processing techniques, which can be used to introduce ceramic particles into copper, is reaction milling [5]. In reaction milling, elemental powders are milled under a certain atmosphere and milling media so that one of the met- als reacts with C, N, or O in order to form carbides, nitrides, or oxides, respectively. During this process, the elemental powders continuously mix, cold-weld and fracture. The fi- nal product after milling generally consists of agglomerated 0921-5093/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.msea.2004.06.036