Thermal and mechanical behavior of CuAlNi single crystals after ageing treatments

V.E.A. ARAUJO; GASTIEN, R.; SADE, M.; LOVEY, F. C.

Workshop; International School on Fundamental Crystalography ?Fourth Ma ThCryst School in Latin America; 2014

IUCr-UNESCO

Cu-14Al-4Ni (wt.%) alloys present properties like shape memory and pseudoelasticity, that make them interesting for technological applications, specially for their low diffusion at temperatures higher than room temperature [1]. This particular behavior is due to martensitic transformations that can be induced from a metastable β phase. Aging thermal treatments of the β-CuAlNi single crystal phase at 473K were conducted in order to study the thermal and mechanical behavior evolution. Incomplete ordering processes started during quenching can be favored by these aging treatments and they can also trigger the decomposition of part of the alloy into more stable phases. The comprehension of the physical mechanisms which take place at temperatures above room temperature and their consequences on the thermomechanical properties, is required for any possible use of the material. Changes on the thermally and stress induced martensitic transformations were observed after ageing treatments at 473K. These include changes in the type of martensite induced, the critical transformations temperatures, the critical stresses and the hysteresis.