Abstract
The influence of aging on the microstructure and mechanical properties of Cu-11.6wt%Al-3.9wt%Ni-2.5wt%Mn shape memory alloy (SMA) was studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometer, and differential scanning calorimeter (DSC). Experimental results show that bainite, γ2, and α phase precipitates occur with the aging effect in the alloy. After aging at 300dgC, the bainitic precipitates appear at the early stages of aging, while the precipitates of γ2 phase are observed for a longer aging time. When the aging temperature increases, the bainite gradually evolves into γ2 phase and equilibrium α phase (bcc) precipitates from the remaining parent phase. Thus, the bainite, γ2, and α phases appear, while the martensite phase disappears progressively in the alloy. The bainitic precipitates decrease the reverse transformation temperature while the γ2 phase precipitates increase these temperatures with a decrease of solute content in the retained parent phase. On the other hand, these precipitations cause an increasing in hardness of the alloy.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
J.I. Pérez-Landazábal, V. Recarte, V. Sánchez-Alarcos, et al., Study of the stability and decomposition process of the β phase in Cu-Al-Ni shape memory alloys, Mater. Sci. Eng. A, 438–440(2006), p.734.
G. Zak, A.C. Kneissl, and G. Zatulskij, Shape memory effect in cryogenic Cu-Al-Mn alloys, Scripta Mater., 34(1996), p.363.
Z.G. Wei, H.Y. Peng, D.Z. Yang, et al., Reverse transformations in CuAlNiMnTi alloy at elevated temperatures, Acta Mater., 44(1996), p.1189.
M.A. Morris, Influence of boron additions on ductility and microstructure of shape memory Cu-Al-Ni alloys, Scripta Metall. Mater., 25(1991), p.2541.
M.A. Morris, High temperature properties of ductile Cu-Al-Ni shape memory alloys with boron additions, Acta Metall. Mater., 40(1992), p.1573.
M.A. Morris and T. Lipe, Microstructural influence of Mn additions on thermoelastic and pseudoelastic properties of Cu-Al-Ni alloys, Acta Metall. Mater., 42(1994), p.1583.
K. Adachi, K. Shoji, and Y. Hamada, Formation of X phases and origin of grain refinement effect in Cu-Al-Ni shape memory alloys added with titanium, ISIJ Int., 29(1989), p.378.
Z.G. Wei, H.Y. Peng, W.H. Zou, and D.Z. Yang, Aging effects in a Cu-12Al-5Ni-2Mn-1Ti shape memory alloy, Metall. Mater. Trans. A, 28(1997), p.955.
U. Sari, Influences of 2.5wt% Mn addition on the microstructure and mechanical properties of Cu-Al-Ni shape memory alloys, Int. J. Miner. Metall. Mater., 17(2010), No.2, p.192.
S. Miyazaki and K. Otsuka, Development of shape memory alloys, ISIJ Int., 29(1989), p.353.
T. Saburi and C.M. Wayman, Crystallographic similarities in shape memory martensites, Acta Metall., 27(1979), p.979.
U. Sari and I. Aksoy, Electron microscopy study of 2H and 18R martensites in Cu-11.92wt% Al-3.78wt% Ni shape memory alloy, J. Alloys Compd., 417(2006), p.138.
U. Sari and T. Kirindi,Effects of deformation on microstructure and mechanical properties of a Cu-Al-Ni shape memory alloy, Mater. Charact., 59(2008), p.920.
H. Cheniti, M. Bouabdallah, and E. Patoor, High temperature decomposition of the β1 phase in a Cu-Al-Ni shape memory alloy, J. Alloys Compd., 476(2009), p.420.
W. Zou, J. Gui, R. Wang, et al., Bainitic precipitation and its effect on the martensitic transformation in the Cu-Al-Ni-Mn-Ti shape-memory alloy, J. Mater. Sci., 32(1997), p.5279.
N. Suresh and U. Ramamurty, Effect of aging on mechanical behavior of single crystal Cu-Al-Ni shape memory alloys, Mater. Sci. Eng. A, 454–455(2007), p.492.
V. Recarte, R.B. Pérez-Sáez, E.H. Bocanegra, et al., Influence of Al and Ni concentration on the martensitic transformation in Cu-Al-Ni shape-memory alloys, Metall. Mater. Trans. A, 33(2002), p.2581.
U. Sari and I. Aksoy, Micro-structural analysis of self-accommodating martensites in Cu-11.92wt% Al-3.78wt% Ni shape memory alloy, J. Mater. Process. Technol., 195(2008), p.72.
A. Aydogdu, Y. Aydogdu, and O. Adiguzel, Long-term ageing behaviour of martensite in shape memory Cu-Al-Ni alloys, J. Mater. Process. Technol., 153-154(2004), p.164.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sari, U., Kirindi, T., Ozcan, F. et al. Effects of aging on the microstructure of a Cu-Al-Ni-Mn shape memory alloy. Int J Miner Metall Mater 18, 430–436 (2011). https://doi.org/10.1007/s12613-011-0458-1
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12613-011-0458-1