The Influence of Post Quench Againg in the Beta-phase on the Transformation Characteristics and the Physical and Mechanical Properties of Martensite in a Cu–Al–Ni Shape Memory Alloy

Abstract

Fine grained Cu–Al–Ni–Ti alloys have been subjected to post quench ageing tretments in the β-phase. The resulting changes in transformation characteristics, particularly As, and the physical and mechanical properties of martensite have been studied. The As shifts are discussed in terms of quenched-in-short range disorder and the subsequent recovery on ageing of first and second neighbour order. The role of order and defects, particularly vacancies, is also discussed in relation to the observed changes in the physical and mechanical properties of martensite. It is also shown that optimising the ageing treatment can lead to the desired properties.