3R and 14M martensitic transformations in as-rolled and annealed Ni64Al34.5Re1.5 shape memory alloy

JOURNAL OF ALLOYS AND COMPOUNDS

卷:509

Article

Kang, Hui-Jang¹  Wu, Shyi-Kaan¹  Wu, Ling-Mei¹ 

[1] Natl Taiwan Univ, Dept Mat Sci & Engn, Taipei 106, Taiwan

关键词: NiAlRe alloy;    Shape memory;    Martensitic transformation;    Microstructure;    X-ray diffraction;    Transmission electron microscopy, TEM;   

DOI  :  10.1016/j.jallcom.2010.11.052

来源: Elsevier

【 摘 要 】

Martensitic transformation of as-rolled and 1323 K x 1 h annealed Ni64Al34.5Re1.5 (NiAl-1.5Re) shape memory alloy (SMA) is investigated. For as-rolled NiAl-1.5Re alloy, TEM and EPMA results indicate both 14M and 3R martensites are observed at the room temperature. 14M is formed in the precipitate-free zone which is a Ni-depletion region and 3R is formed in the matrix which is a Ni-enrichment region. XRD and partial-cycle DSC testing results show that the higher temperature peak of the DSC cooling curve is B2 -> 14M and the lower one is B2 -> 3R. Hardness tests show that 14M hardness is higher than that of 3R. For annealed NiAl-1.5Re alloy, only B2 <-> 3R can be observed. The critical value for the formation of 14M martensite in NiAl-1.5Re alloy is about 63.6 at.% Ni, as compared to 63.0 at.% Ni for Ni-Al binary SMAs. (C) 2010 Elsevier B.V. All rights reserved.

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