A comparative study of the post-quench behavior of Cu-Al-Be and Cu-Zn-Al shape memory alloys
- Univ. de Barcelona (Spain). Dept. d`Estructura i Constituents de la Materia; and others
This paper reports a comparative investigation of the effect of quenching on the Cu-Al-Be and Cu-Zn-Al shape memory alloys by the use of several experimental techniques. In a first stage, the order-disorder transitions in these alloys have been characterized by means of modulated calorimetry. Results have proved that the A2 {l_equilibrium} DO{sub 3} transition in Cu-Al-Be is first order with a latent heat of 1,160 J/mol; the B2 {l_equilibrium} L2{sub 1} transition in Cu-Zn-Al is second order, and a peak in the specific-heat vs temperature curve has been observed. Secondly, the post-quench behavior of these alloys, when subjected to some of the typical heat treatments used to stabilize the {beta} phase, has also been studied by means of neutron diffraction, positron annihilation and highly sensitive calorimetry. A different post-quench time evolution of the martensitic transition temperatures has been found for the two alloys. For Cu-Al-Be, this evolution has been shown to be correlated with positron annihilation data, while, for Cu-Zn-Al, a correlation with neutron diffraction data has been established. These results show that the measured shifts in the transition temperatures induced by a quench are mostly due to an excess of vacancies in the case of Cu-Al-Be, and to an incomplete degree of L2{sub 1} atomic order in Cu-Zn-Al.
- OSTI ID:
- 599880
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 3 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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