Cyclic deformation and austenite stabilization in Co₃₅Ni₃₅Al₃₀ single crystalline high-temperature shape memory alloys

verfasst von

J. Dadda, H. J. Maier, I. Karaman, Y. I. Chumlyakov

Abstract

This study reports on the role of repeated stress-induced martensite (SIM) transformations on the pseudoelastic (PE) behavior of solutionized Co₃₅Ni₃₅Al₃₀ [0 0 1]-oriented shape memory single crystals under both isothermal and non-isothermal conditions (referred to as "training"). It is demonstrated that training results in austenite stabilization and strengthening, consequently increasing the critical transformation stress levels for the SIM (σ_crit^SIM), and promoting excellent cyclic stability and reproducibility of the PE response. This is attributed to the formation of dense dislocation arrangements and fine coherent sub-nanometer hexagonal close-packed Co and γ′ (Ni₃Al:L1₂) precipitates during training. The training that involved cyclic loading conditions was more effective than the monotonic stress-strain tests at different temperatures in modifying SIM characteristics bringing about (i) a large pseudoelastic temperature range of 350 °C with σ_crit^SIM levels reaching 1 GPa with complete recoverable strains of 2%, and (ii) excellent stable cyclic PE response at temperatures as high as 250 °C.

Externe Organisation(en)

Universität Paderborn
Texas A and M University
Tomsk State University

Typ

Artikel

Journal

Acta materialia

Band

57

Seiten

6123-6134

Anzahl der Seiten

12

ISSN

1359-6454

Publikationsdatum

12.2009

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Elektronische, optische und magnetische Materialien, Keramische und Verbundwerkstoffe, Polymere und Kunststoffe, Metalle und Legierungen

Elektronische Version(en)

https://doi.org/10.1016/j.actamat.2009.08.038 (Zugang: Unbekannt)