Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/85439
Title: Martensite stabilization and thermal cycling stability of two-phase NiMnGa-based high-temperature shape memory alloys
Authors: Yang, Shuiyuan.
Liu, Yong.
Wang, Cuiping.
Liu, Xingjun.
Issue Date: 2012
Source: Yang, S., Liu, Y., Wang, C., & Liu, X. (2012). Martensite stabilization and thermal cycling stability of two-phase NiMnGa-based high-temperature shape memory alloys. Acta Materialia, 60(10), 4255-4267.
Series/Report no.: Acta materialia
Abstract: The martensite stabilization and thermal cycling stability of four types of two-phase NiMnGa-based high-temperature shape memory alloy, including Ni56+xMn25Ga19−x (x = 0, 1, 2, 3, 4), Ni56Mn25−yFeyGa19 (y = 4, 8, 9, 12, 16), Ni56Mn25−zCozGa19 (z = 4, 6, 8) and Ni56Mn25−wCuwGa19 (w = 2, 4, 8) alloys, were investigated. It is found that the martensite stabilization is closely related to the strength of the alloy and the volume fraction of γ phase; and increases as the alloy strength decreases. It is also found that in Ni56Mn25−yFeyGa19 alloys, with increasing Fe content to 12 and 16 at.%, the volume fraction of γ phase increases and the martensite stabilization decreases. The thermal cycling stability differs among different alloy systems and is related to the microstructural changes during thermal cycling and to the strength of the γ phase. Poor thermal cycling stability is observed in Ni56+xMn25Ga19−x (x > 0), Ni56Mn25−zCozGa19 and Ni56Mn25−wCuwGa19 alloys due to the formation of the ordered γ′ phase and the high strength of the γ phase. Results further show that Fe addition to Ni56Mn25Ga19 alloy can broaden the (bcc + γ) two-phase region and shift it to the Ni–Ga and Ni–Mn sides, hence stabilizing the two-phase region to lower temperatures. These effects can retard the formation of the ordered γ′ phase in the Ni56Mn25−yFeyGa19 system during thermal cycling, thus leading to good thermal cycling stability.
URI: https://hdl.handle.net/10356/85439
http://hdl.handle.net/10220/10365
ISSN: 1359-6454
DOI: http://dx.doi.org/10.1016/j.actamat.2012.04.029
Rights: © 2012 Acta Materialia Inc.
Fulltext Permission: none
Fulltext Availability: No Fulltext
Appears in Collections:MAE Journal Articles

Google ScholarTM

Check

Altmetric

Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.