Twinning processes in Cu-Al-Ni martensite single crystals investigated by neutron single crystal diffraction method

0312558 - ÚJF 2013 RIV CH eng J - Journal Article
Molnar, P. - Šittner, P. - Novák, V. - Lukáš, Petr
Twinning processes in Cu-Al-Ni martensite single crystals investigated by neutron single crystal diffraction method.
Materials Science and Engineering A Structural Materials Properties Microstructure and Processing. Roč. 481, Sp.Iss.SI (2008), s. 513-517. ISSN 0921-5093. E-ISSN 1873-4936
R&D Projects: GA AV ČR IAA100480704
Institutional research plan: CEZ:AV0Z10480505
Keywords : Cu-Al-Ni * single crystals * neutron diffraction
Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders
Impact factor: 1.806, year: 2008

A neutron single crystal diffraction method for inspecting the quality of martensite single crystals is introduced. True interface-free martensite single crystals are indispensable for, e.g. measurement of elastic constants of phases by ultrasonic techniques. The neutron diffraction method was used to detect and distinguish the presence of individual lattice correspondence variants of the 2H orthorhombic martensite phase in Cu-Al-Ni as well as to follow the activity of twinning processes during the deformation test on the martensite variant single crystals. When preparing the martensite single variant prism-shaped crystals by compression deformation method, typically a small fraction of second unwanted martensitic variant (compound twin) remains in the prism samples. Due to the very low stress (similar to 1 MPa) for the compound twinning in many shape memory alloys, it is quite difficult not only to deplete the martensite prisms of all internal interfaces but mainly to keep them in the martensite single variant state for a long time needed for further investigations.
Permanent Link: http://hdl.handle.net/11104/0163589