J. Phys. IV France 112 (2003) 499
DOI: 10.1051/jp4:2003933

The effect of DO ₃/ L2 ₁ phase separation on the martensitic transition of Cu-A1-Mn shape-memory alloys

J. Marcos¹, LI. Manosa¹, A. Planes¹, R. Romero² and M.L. Castro<sup>3

1</sup>  Departament d'Estructura i Constituents de la Matèria, Facultat de Fisica, Universitat de Barcelona, Digonal 647, 08028 Barcelona, Catalonia, Spain
²  IFIMAT, Universidad del Centro de la Provincia de Buenos Aires and Comision de Investigaciones Cientificas de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil, Argentina
³  IFIMAT, Universidad del Centro de la Provincia de Buenos, Pinto 399, 7000 Tandil, Argentina

Abstract
In this paper we show that a magnetic-induced phase separation between Cu ₃A1-rich and Cu ₂A1Mn-rich domains occurs below the L2₁-ordering temperature in alloys with compositions along the Cu ₃A1 Mn line. We study the influence of such a phase separation on the magnetic properties and on the martensitic transition undergone by Cu-A1-Mn alloys. Results indicate that during the phase separation process, the ferromagnetic character of the system is enhanced as a consequence of the formation of Mn-rich clusters. This leads to an increase in the martensitic transition temperature and to a decrease of the entropy change.

© EDP Sciences 2003