Composition and temperature dependence of twinning stress in non-modulated martensite of Ni-Mn-Ga-Co-Cu magnetic shape memory alloys

0489254 - FZÚ 2019 RIV US eng J - Článek v odborném periodiku
Soroka, A. - Sozinov, A. - Lanska, N. - Rameš, Michal - Straka, Ladislav - Ullakko, K.
Composition and temperature dependence of twinning stress in non-modulated martensite of Ni-Mn-Ga-Co-Cu magnetic shape memory alloys.
Scripta Materialia. Roč. 144, Feb (2018), s. 52-55. ISSN 1359-6462. E-ISSN 1872-8456
Grant CEP: GA ČR GA16-00043S
Institucionální podpora: RVO:68378271
Klíčová slova: Heusler phases * martensite * ferromagnetic shape memory alloy * magnetic shape memory * twinning
Obor OECD: Condensed matter physics (including formerly solid state physics, supercond.)
Impakt faktor: 4.539, rok: 2018

We study compositional and thermal dependences of lattice parameters and twinning stress σTW in Ni50-xMn25-yGa25-zCoxCuy+z magnetic shape memory alloys with non-modulated tetragonal crystal structure. The σTW was found to decrease with increasing temperature with a slope from −0.0076 to −0.0181 MPa/K. The σTW = 0.47–0.81 MPa values measured near composition-specific austenite transformation temperatures TA were discovered to depend linearly on the c/a ratio with a slope of 14 MPa. We predict that the further decrease of c/a ratio to the level of 1.085–1.104 can result in extremely low σTW ≈ 0.1 MPa in non-modulated martensite.
Trvalý link: http://hdl.handle.net/11104/0283699