Long range ordering in Beta-Cu-Zn-Al: Experimental and theoretical study

F. LANZINI; R. ROMERO; M. STIPCICH; M. L. CASTRO

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

The American Physical Society

Lugar: Ridge, NY; Año: 2008 vol. 77 p. 134207 - 134215

0163-1829

We present the order-disorder transition temperatures for bcc Cu-Zn-Al shape memory alloys measured by means of resistometric and calorimetric techniques. The investigation includes the line of compositions Cu0.76-x/2 - Znx - Al0.24-x/2 (0 <= x <= 0.48), i. e., the line with a constant conduction electron to atom ratio, e/a=1.48. Experimental results are confronted with Monte Carlo simulations based on the Blume-Emery-Griffiths Hamiltonian. A set of exchange energies in first and second neighbours is calculated, which allows in close agreement reproduction of the experimental phase diagram.