The Influence of Aging on Critical Transformation Stress Levels and Martensite Start Temperatures in NiTi: Part I—Aged Microstructure and Micro-Mechanical Modeling

Journal of Engineering Materials and Technology - Tập 121 Số 1 - Trang 19-27 - 1999
Ken Gall1, Hüseyin Şehitoğlu1, Y.I. Chumlyakov2, И. В. Киреева2, Hans Jürgen Maier3
1Department of Mechanical and Industrial Engineering, University of Illinois, Urbana, IL, 61801
2Physics of Plasticity and Strength of Materials Laboratory, Siberian Physical and Technical Institute, 634050 Tomsk, Russia
3Institute F. Werkstofftechnik, Universita¨t-GH-Siegen, D-57068, Siegen, Germany

Tóm tắt

Transmission electron microscopy is used to determine the microstructures of a Ti-50.8 at% Ni alloy given different aging treatments. Two different peak-aging treatments are shown to result in disk shaped semi-coherent Ti3Ni4 precipitates with a diameter ranging from 50 nm to 200 nm depending on the aging temperature. In the peak-aged materials, strong strain fields are clearly visible on TEM micrographs. An Eshelby based model is used to predict the local stress fields due to the differences in the lattice parameters of the precipitates and surrounding matrix. The position dependent local stress fields are then resolved onto the 24 different martensite correspondence variant pairs (CVP’s). It is further demonstrated that due to the unique orientation relationship that exists between the precipitate variants and the martensite CVP’s, the local resolved shear stresses are extremely large on some CVP’s and negligible on others. When the Ni rich NiTi is over-aged, it is found that the precipitates coarsen to approximately 1000nm, they become in-coherent, and the local stress fields disappear. It is also determined that after over-aging the average composition of the matrix drops from 50.8 at% Ni to approximately 50.4 at% Ni. In a subsequent paper (part II) the results here are used to explain the dependence of the critical transformation stress levels and martensite start temperatures on the aging treatment.

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Tài liệu tham khảo

Abujudom D. N. , ThomaP. E., and FariabiS., 1990, “The Effect of Cold Work and Heat Treatment on the Phase Transformations of Near Equiatomic NiTi Shape Memory Alloy,” Mat. Sci. Forum, Vol. 56–58, pp. 565–570.

Beyer, J., Brakel, R. A., and Lloyd, J. R. T., 1986, “Precipitation Processes in TiNi Near Equiatomic Alloy,” ICOMAT-86, pp. 703–708.

Buchheit T. E. , and WertJ. A., 1994, “Modeling the Effects of Stress State and Crystal Orientation on the Stress-Induced Transformation of NiTi Single Crystals,” Metall. Mater. Trans., Vol. 25A, pp. 2383–2389.

Buchheit T. E. , WertJ. A., 1996, “Predicting the Orientation-Dependent Stress-induced Transformation and Detwinning Response of Shape Memory Alloy Single Crystals,” Metall. Mater. Trans., Vol. 27A, pp. 269–279.

Chumlyakov Y. I. , and StarenchenkoS. V., 1995, “Stress-Induced Martensitic Transformation in Aged Titanium Nickel Single Crystals,” J. Phys. IV, Colloq, Vol. 5, pp. 803–807.

Chumlyakov Y. I. , KireevaI. V., LineytsevV. N., and ChepelE. V., 1996, “Aging influence on the shape memory effects and superelasticity in Titanium-Nickel Single crystals,” MRS Symposium Proceedings, Vol. 459, Boston, pp. 387–392.

Duerig, T. W., and Pelton, A. R., 1994, “Ti-Ni Shape Memory Alloys,” Mater. Prop. Hnbk., ASM International, Titanium Alloys, pp. 1035–1048.

Gall, K., Sehitoglu, H., Chumlyakov, Y., Kireeva, Y. I., and Maier, H. J., 1998, “The Influence of Aging on Critical Transformation Stress Levels and Martensite Start Temperatures in NiTi: Part II—Discussion of Experimental Results,” ASME JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY, published in this issue pp. 28–37.

Gall K. , SehitogluH., ChumlyakovY., ZuevY., and KaramarI., 1998A, “The Role of Coherent Precipitates in Martensitic Transformations in Single Crystal and Polycrystalline Ti-50.8 at %Ni,” Scnpta Materialia, Vol. 39, No. 6, pp. 699–706.

Honma, T., 1986, “The Effect of Aging on the Spontaneous Shape Change and the All-Round Shape Memory Effect in Ni-Rich TiNi Alloy,” ICOMAT-86, pp. 709–716.

Hornbogen E. , 1985, “The effect of Variables on Martensitic Transformations Temperatures,” Acta. Mett., Vol. 33, pp. 595–601.

Lieberman D. S. , WechslerM. S., and ReadT. A., 1955, “Cubic to Orthorombic Diffusionless Phase Change-Experimental and Theoretical Studies of AuCd,” J. App. Phys., Vol. 26, pp. 473–484.

Li D. Y. and ChenL. Q., 1997-1, “Selective Variant Growth of Coherent Ti11 Ni14 precipitate in a TiNi Alloy Under Applied Stress,” Acta Mater., Vol. 45, pp. 471–479.

Li D. Y. and ChenL. Q., 1997-11, “Shape of a Rhombohedral Coherent Ti11 Ni14 precipitate in a Cubic Matrix and its Growth and Dissolution During Constrained Aging,” Acta Mater., Vol. 45, pp. 2435–2442.

Madangopal K. , 1997, “The Self Accommodating Martensitic Microstructure of Ni-Ti Shape Memory Alloys,” Acta Mater., Vol. 45, pp. 5347–5365.

Martin, J. W., 1980, Micromechanisms in Particle-Hardened Alloys, 1st edition, Cambridge University Press, Great Britian, p. 17.

Matsumoto O. , MiyazakiS., OtsukaK., and TamuraH., 1987, “Crystallography of Martensitic Transformations in Ti-Ni Single Crystals,” Acta. Mett., Vol. 35, pp. 2137–2144.

Miyazaki S. , OhmiY., OtsukaK., and SuzukiY., 1982, “Characteristics of Deformation and Transformation Pseudoelasticity in Ti-Ni Alloys,” J. De. Phys., C-4, Vol. 43, p. 255255.

Miyazaki S. , KimuraS., OtsukaK., and SuzukiY., 1984, “The Habit Plane and Transformation Strains Associated With the Martensitic Transformation in Ti-Ni Single Crystals,” Scr. Mett., Vol. 18, pp. 883–888.

Miyazaki S. , OtsukaK., and WaymanC. M., 1989, “The Shape Memory Mechanism Associated with the Martensitic Transformation in Ti-Ni Alloys—I. Self Accommodation,” Acta. Mett., Vol. 37, pp. 1873–1884.

Miyazaki S. , OtsukaK., and WaymanC. M., 1989, “The Shape Memory Mechanism Associated with the Martensitic Transformation in Ti-Ni Alloys—II. Variant Coalescence and Shape Recovery,” Acta. Mett., Vol. 37, pp. 1885–1890.

Mura, T., 1987, Micromechanics of Defects in Solids, 2nd edition, Kluwer Academic Publishers, The Netherlands.

Nishida M. , WaymanC. M., and HonmaT., 1986, “Precipitation Processes in Near-Equiatomic TiNi Shape Memory Alloys,” Met. Trans., Vol. 17A, pp. 1505–1515.

Nishida M. , WaymanC. M., 1988, “Electron Microscopy Studies of the ‘premartensitic’ Transformations in an Aged Ti-51 at.% Ni Shape Memory Alloy,” Metallography, Vol. 21, pp. 255–273.

Nishida M. , WaymanC. M., ChibaA., 1988, “Electron Microscopy Studies of the Martensitic Transformation in an Aged Ti-51 at.% NI Shape Memory Alloy,” Metallography, Vol. 21, pp. 275–291.

Otsuka K. , WaymanC. M., NakaiK., SakamotoH., and ShimizuK., 1976, “Superelasticity Effects and Stress-Induced Martensitic Transformations in Cu-Al-Ni- Alloys,” Acta. Matall., Vol. 24, pp. 207–226.

Ramanujan R. V. , AaronsonH. I., and LeoP. H., 1997, “The Role of Boundary Conditions in Modeling the Elastic Fields around a Misfitting Precipitate,” Meta. Trans. Comm., Vol. 20A, pp. 1277–1279.

Tadaki T. , NakadaY., ShimizuK., OtsukaK., 1986, “Crystal Structure, Composition and Morphology of a Precipitate in an Aged Ti-51 at % Ni Shape Memory Alloy,” Trans. JIM, Vol. 27, pp. 731–740.

Todoroki T. and TamuraH., 1987, “Effect of Heat Treatment after Cold Working on the Phase Transformation in TiNi alloy,” Trans. Jpn. Inst. Met., Vol. 28, No. 2, pp. 83–94.

Treppmann D. , and HornbogenE., 1995, “The Effect of Dislocation Substructure and Decomposition on the Course of Diffusionless Transformation,” J. D. Physique IV, Vol. 5, pp. 211–216.

Treppmann D. , HornbogenE., and WurzelD., 1995, “The Effect of Combined Recrystallization and Precipitation Processes on the Functional and Structural Properties of NiTi Alloys,” J. De. Phys., Vol. 5, pp. 569–574.

Wayman, C. M., 1986, “Phase Transformations in Ni-Ti Shape Memory Alloys,” ICOMAT 86, p. 645.

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Journal of Engineering Materials and Technology

Tập 121 Số 1

19-27

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