On the transitions of the 2H martensite single variant of CuAlMn alloy

S. Ignacová^{1, 2}, V. Novák¹, P.Šittner¹

¹Institute of Physics AS CR, Na Slovance 2, 182 21 Prague 8, Czech Republic

²Faculty of Nuclear Sciences and Physical Engineering CTU, Břehová 7, 11519 Prague 1, Czech Republic

E-mail: ignacova@fzu.cz

The method of successive compression loads to different faces of prism shaped shape memory alloy (SMA) single crystal specimens has been presented as an efficient approach to investigate twinning deformation processes in martensitic phases [1]. This approach (developed originally on CuAlNi single crystals) is applied in the present work and is concerned with the investigation of the twinning processes in the 2H martensite phase in CuAlMn SMAs.

Two single crystalline CuAlMn alloys of various chemical compositions (e/a ratio) in a form of prismatic samples were subjected to compression experiments [2]. Twinning deformation processes in the martensite were investigated by the i) compression stress-strain responses recorded for multiple load axis orientations, ii) measurements of shape changes due to the reorientation of martensite single variants, and iii) the three surface trace analysis method for the characterization of twining planes. The experimental results were discussed and compared with theoretical calculations of the type of twinning, a value of twinning stresses, its orientation dependence etc. Finally, the results of stress-strain behavior of this alloy were compared with behavior of CuAlNi shape memory alloy and is shown the advantage of the shape changes measurements according to the martensite variant determination where the variant existing in the sample can be clearly determined in comparison with other methods (Back Laue reflection method).

1. V. Novák, P. Šittner, S. Ignacová and T. Černoch, Mat. Sci. Eng A (2006) in print.

2. N. Zárubová, V. Novák, Mater. Sci. and Eng. A 378 (2004) 216–221.