J. Phys. IV France 05 (1995) C2-275-C2-280
Pseudoelastic Deformation of CuAlMn Single CrystalsJ. Dutkiewicz1, M. Bartsch2, S. Miura3, U. Messerschmidt2 and H. Kato3
1 Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 30-059 Krakow, ul. Reymonta 25, Poland
2 Max-Planck-Institute of Microstructure Physics, Halle Weinberg 2, D-06120, Germany
3 Department of Engineering Science, Faculty of Engineering, Kyoto University, Kyoto 606-01, Japan
Martensitic transformation associated with a tensile deformation of CuAlMn single crystals in  direction was studied using in-situ transmission electron microscopy. Stress/strain curves obtained during pseudoelastic deformation of microscopic samples were slightly different from bulk ones due to martensite formation in the stage of stress increase and a permanent deformation during the first cycle. Individual needles of 2H martensite were formed already in the early deformation stage. They were growing during stress increase, joining together into large plates. At later deformation stages 18R martensite was formed usualy in stacks of single plates. Following crystallographic relationship between parent and martensitic phases was observed : β1||γ',β'andβ1||γ',β'. At a high stress concentration near crack tips, α' martensite of 3R lattice was observed. Identification of martensite structure was very often not possible there, due to an extremely high random stacking faults density.
© EDP Sciences 1995