Role of antisite disorder in the martensitic transition of Ni2−xMn1+xGa. (September 2022)

• Record Type: Journal Article
• Authors: Malik, S.V.; Dias, E.T.; Srihari, V.; Babu, P.D.; Priolkar, K.R.
• Is Part Of: Intermetallics. Volume 148(2022)
• Publication Date: 2022-09
• Subjects: Mn2NiGa -- Martensite transformation -- Heusler alloys; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2022.107613
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: A systematic investigation of the structure and local structure of Ni2− x Mn1+ x Ga alloys 0 ≤ x ≤ 1 reveals antisite disorder to be a possible reason for higher martensitic transformation temperature of Mn2 NiGa as compared to Ni2 MnGa. The antisite disorder between the Y and Z sublattices of the X2 YZ Heusler structure results in segregation of Mn3 Ga type defect phase and a Ni-rich Heulser phase with a higher e/a ratio. This Ni-rich Heusler phase appears to be responsible for the higher martensitic transformation temperature of the Mn2 NiGa type Heusler alloys. Highlights: Mn2 NiGa displays higher martensitic transformation temperature than Ni2 MnGa despite its lower e/a ratio. Antisite disorder between Y and Z sub lattices of X2 YZ Heusler structure exists in Mn2 NiGa. The antisite disorder segregates Mn3 Ga and Ni-rich Heusler defect phases in Ni2-x Mn1+x Ga alloys. The Ni-rich Heusler phase with a higher e/a ratio is responsible for the higher martensitic transformation temperature.