Abstract
A method has been developed to produce grain sizes as small as 5 μm in alloys of β-CuAlNi. The alloys were of eutectoid composition and a procedure was developed for determining the composition of a eutectoid alloy having any required value for transition temperature (M s ). The thermo-mechanical treatment involved two sequential stages of warm rolling followed by recrystallization. The alloys produced were single phase β-type with no second phase being present. Characteristic two-stage stress-strain curves were obtained for most of the specimens. It was generally found that the tensile strength and strain to failure increased with decreasing grain size according to a Hall-Petch type relationship down to a grain size of 5 μm. A fracture strength of 1200 MPa and a fracture strain of 10 pct were obtained in the best alloy. It was found that the major recovery mode, whether pseudoelastic or strain-memory, did not have any significant effect on the total recovery obtained. Recovery properties were not affected significantly by decreasing grain size, and 86 pct recovery could still be obtained at a grain size of around 10 μm. Grain refinement improved the fatigue life considerably, possibly due to the high ultimate fracture stress and ductile fracture mode. A fatigue life of 275,000 cycles could be obtained for an applied stress of 330 MPa and a steady state strain of 0.7 pct. At fine-grain sizes most of the fractures were due to transgranular-type brittle fracture and micro void-type ductile fracture, depending on the alloy composition. It was suggested that the difference between the alloys was due to differences in oxygen segregation at the grain boundaries.
Similar content being viewed by others
References
L. Delaey, R. V. Krishnan, H. Tas, and H. Warlimont:J. Materials Science, 1974, vol. 9, pp. 1521-35, 1536-44, 1545–55.
K. Otsuka, H. Sakamoto, and K. Shimizu:Acta Metall., 1979, vol. 27, pp. 585–601.
J. S. Lee and C.M. Wayman:Trans. Jap. Inst. Met., 1986, vol. 27, pp. 584–91.
A.Q. Khan and L. Delaey:Zeit für Metalkunde, 1969, vol. 60, pp. 949–51.
A.Q. Khan and L. Delaey:Scripte Metall., 1970, vol. 4, pp. 981–83.
G.N. Sure and L. C. Brown:Metall. Trans. A, 1984, vol. 15A, pp. 1613–21.
G.N. Sure and L. C. Brown:Scripta Metall., 1985, vol. 19, pp. 401–04.
T. W. Duerig, J. Albrecht, and G.H. Gessinger:Journal of Metals, 1982, vol. 34, pp. 14–20.
J. Jassen, F. Willems, B. Vereist, J. Maertens, and L. Delaey:Proc. of ICOMAT-82, L. Delaey and M. Chandrasekaran, eds., Leuven, Belgium, 1982, pp. C4809-C4812.
J.V. Wood:Proc. of ICOMAT-82, L. Delaey and M. Chan- drasekaran, eds., Leuven, Belgium, 1982, pp. C4755-C4760.
C. Oshima, M. Tanimoto, T. Oka, F. E. Fujita, Y. Hanadate, and M. Miyagi:Proc. of ICOMAT-82, L. Delaey and M. Chandrasekaran, eds., Leuven, Belgium, 1982, pp. C4749-C4754.
S. Eucken, P. Donner, and E. Hornbogen:Proc. Int. Conf. Phase Transformations, G.W. Lorimer and N. Ridley, eds., Cambridge, England, 1987.
K. Kamei, H. Matsumoto, K. Sugimoto, and T. Irizawa:J. Japan Copper Research Association, 1981, vol. 19, pp. 201–11.
K. Sugimoto, K. Kamei, H. Matsumoto, S. Komatsu, K. Akamatsu, and T. Sugimoto:Proc. of ICOMAT-82, L. Delaey and M. Chandrasekaran, eds., Leuven, Belgium, 1982, pp. C4761-C4766.
K. Enami, N. Takimoto, and S. Nenno:Proc. of ICOMAT-82,L. Delaey and M. Chandrasekaran, eds., Leuven, Belgium, 1982, pp. C4773-C4778.
P. Furrer:First Riso Int. Symp. on Metallurgy and Materials Sci- ence, N. Hansen, A. R. Jones, and T. Leffers, eds., Roskilde, Den- mark, 1980, pp. 109–14.
J. G. Byrne:Recovery, Recrystallization and Grain Growth, MacMillan, New York, NY, 1965, pp. 60–92.
W.O. Alexander:J. Inst. Metals, 1938, vol. 63, pp. 163–89.
H. Warlimont and L. Delaey:Prog. Materials Science, 1974, vol. 18, pp. 1–146.
D. Hull and R.D. Garwood:J. Inst. Met., 1957-1958, vol. 86, pp. 485–92.
W. A. Rachinger:J. Aust. Inst. Metals, 1960, vol. 5, pp. 114–17.
K. Oishi and L. C. Brown:Metall. Trans., 1971, vol. 2, pp. 1971–77.
H. Sakamoto:Trans. Jap. Inst. Metals, 1983, vol. 24, pp. 665–73.
M. Yasunaga, Y. Funatsu, S. Kojima, K. Otsuka, and T. Suzuki:Proc. of ICOMAT-82, L. Delaey and M. Chandrasekaran, eds., Leuven, Belgium, 1982, pp. C4603-C4608.
Y. Ikai, K. Murakami, and K. Mishima:Proc. of ICOMAT-82, L. Delaey and M. Chandrasekaran, eds., Leuven, Belgium, 1982, pp. C4785-C4789.
S. Miyazaki, T. Kawai, and K. Otsuka:Proc. of ICOMAT-82, L. Delaey and M. Chandrasekaran, eds., Leuven, Belgium, 1982, pp. C4813-C4818.
I. Dvorak and E. B. Hawbolt:Metall. Trans. A, 1975, vol. 6A, pp. 95–99.
R. W. Armstrong:Metall. Trans., 1970, vol. 1, pp. 1169–76.
R. W. Armstrong, Y. T. Chou, R. A. Fisher, and N. Louat:Philos. Mag., 1966, vol. 14, pp. 943–51.
S. M. White, J. M. Cook, and W. M. Stobbs:Proc. of ICOMAT-82, L. Delaey and M. Chandrasekaran, eds., Leuven, Belgium, 1982, pp. C4779-C4783.
A.H. Kasberg and D.T. Mack:Trans. TMS-AIME, 1951, vol. 191, pp. 903–08.
W. Arneodo and M. Ahlers:Acta Metall., 1974, vol. 22, pp. 1475–80.
K. N. Melton and O. Mercier:Acta Metall, 1981, vol. 29, pp. 393–98.
A.W. Thompson and W.A. Backofen:Acta Metall., 1971, vol. 19, pp. 597–606.
R. Oshima and Y. Oshida:Proc. of ICOMAT-82, L. Delaey and M. Chandrasekaran, eds., Leuven, Belgium, 1982, pp. C4803-C408.
F. Borik, W. M. Justusson, and V.F. Zackay:Trans. ASM, 1963, vol. 56, pp. 327–28.
S. Miyazaki, K. Otsuka, H. Sakamoto, and K. Shimizu:Trans. Jap. Inst. Metals, 1981, vol. 22, pp. 244–52.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mukunthan, K., Brown, L.C. Preparation and properties of fine grain β- CuAlNi strain- memory alloys. Metall Trans A 19, 2921–2929 (1988). https://doi.org/10.1007/BF02647718
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02647718