TiNb-esaslı β-Ti Alaşımlarının Kristal Yapı, Mikroyapı ve Dönüşüm Sıcaklıklarına Tantal Katkısının Etkileri

β-tipi Ti-esaslı alaşımlar yüksek sıcaklıktaki dayanıklılığı ve biyo-uyumluluğu sayesinde uzay sanayisi ve medikal alanlarda kullanımı yaygın olan materyallerdir. Nb ve Ta gibi düşük yoğunluklu, üstün korozyon direnci ve toksik olmayan özelliklere sahip elementler ile takviye edilmesi, β-tipi Ti-esaslı alaşımları daha da çekici hale getirmiştir. TiNb(24,5-x)Ta(x=0,1,2,3,4) (at. %) oranlarında hazırlanan alaşımların X-ışını, mikroyapı ve dönüşüm sıcaklıkları incelendi. DSC analizlerinden 5,5 oC to 41,1 oC aralığında sadece α→β ters dönüşümü gözlenmiştir. Oda sıcaklığında yapılan XRD analizleri ile DSC sonuçlarının uyumlu olduğu görülmüştür. Baskın β fazlarına karşın α fazlarının küçük miktarlar da olduğu tespit edilmiştir. β fazının baskın olması Ta ve Nb elementlerinin iyi bir β stabilizatörü olduğunu göstermiştir. Optik mikroskop görüntülerinden alaşımlardaki β fazı, taneler ve tane sınırlarının artan Ta ilavesiyle belirginleşmiştir. SEM-EDX görüntülerinden α fazının çökelti olduğu görülmüştür. Ayrıca EDX sonuçları ile Ta element konsatrasyonunun tane sınırlarında arttığı bulunmuştur. Alaşımların (ev⁄a) ve (cv ) oranları oda sıcaklığı altında dönüşüm sergileyen düşük değerli (ev⁄a

Anahtar Kelimeler:

β-tipi Ti, kristal yapı, mikroyapı, ters dönüşümlü martensit

The Effects of Tantalum Additive on the Crystal Structure, Microstructure and Transformation Temperatures of TiNb-based β-Ti Alloys

β-type Ti-based alloys are materials which widely used in the aerospace industry and medical fields because it has a sufficient biocompatibility and high temperature resistance. Reinforcement with low-density, high corrosion resistance and non-toxic elements, such as Nb and Ta alloying with β-type of Ti-based alloys even more attractive. X-ray, microstructure, and transformation temperatures of TiNb(24,5-x)Ta(x = 0,1,2,3,4) (at. %) alloys were investigated. The DSC analysis showed only α→β reverse transformation for the temperature range of 5,5 oC to 41,1 oC. DSC results were found to be compatible with X-ray analysis taken at room temperature. It was found that α phases were in small amounts despite dominant β phases. The dominance of the β phase has shown that the Ta and Nb elements are a good β stabilizer. It was determined from the optical microscope images that the β phase, grains, and grain boundaries in alloys increased with the addition of Ta. From SEM-EDX results, it was found that α phase is a precipitation. Additionally, the EDX results showed that Ta elements concentration increased in the grain boundaries. Valance electron concentration (ev⁄a) and concentration of valance electron (cv ) values indicated that the alloy with low values of (ev⁄a

Keywords:

β-type Ti, crystal structure, microstructure, reverse martensite,

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Zhou Y.L., Mitsuo N., Toshikazu A., Hisao F., Hiroyuki T. 2005. Corrosion resistance and biocompatibility of Ti–Ta alloys for biomedical applications. Materials Science and Engineering: A, 398 (1-2): 28-36.
Kim H., Hashimoto S., Kim J.I., Hosoda H., Miyazaki S. Effect of Ta addition on shape memory behavior of Ti–22Nb alloy. 2006. Materials Science and Engineering: A, 417 (1-2): 120-128.
Lopes, E., Cremasco A., Afonso C., Caram R. 2011. Effects of double aging heat treatment on the microstructure, Vickers hardness and elastic modulus of Ti–Nb alloys. Materials characterization, 62 (7): 673-680.
García-Garrido, C., Gonzalez-Gutierrez C., Torrecillas R., Perz-Pozo L., Salvo C., Chicardi. 2019. Manufacturing optimisation of an original nanostructured (beta+ gamma)-TiNbTa material. Journal of Materials Research and Technology, 8 (3): 2573-2585.
Dagdelen F., E Ercan. 2014. The surface oxidation behavior of Ni–45.16% Ti shape memory alloys at different temperatures. Journal of Thermal Analysis and Calorimetry, 115 (1): 561-565.
Dagdelen F., Kok M., Qader I. 2019. Effects of Ta content on thermodynamic properties and transformation temperatures of shape memory NiTi alloy. Metals and Materials International, 25 (6): 1420-1427.
Kent D., Wang G., Dargusch M. 2013. Effects of phase stability and processing on the mechanical properties of Ti–Nb based β Ti alloys. Journal of the Mechanical Behavior of Biomedical Materials, 28: 15-25.
Hussein A., Mohamed A., Ahmad M., Sherif K. 2014. Effect of heat treatment on the microstructure of Ti–Nb–Ta base alloys for biomedical applications. Int. J. Chem. Appl. Biol. Sci, 1: 119.
Mantani Y., Tajima M. 2006. Phase transformation of quenched α ″martensite by aging in Ti–Nb alloys. Materials Science and Engineering: A, 438: 315-319.
Dubinskiy S., Prokoshkin S., Brailovski V., Inaekyan K., Korotitskiy A. 2014. In situ X-ray diffraction strain-controlled study of Ti–Nb–Zr and Ti–Nb–Ta shape memory alloys: crystal lattice and transformation features. Materials characterization, 88: 127-142.
Dubinskiy S., Prokoshkin S.D., Brailovski V., Inaekyan K.E., Korotitskiy A.V., Filonov M.R., Petrzhik M.I. 2011. Structure formation during thermomechanical processing of Ti-Nb-(Zr, Ta) alloys and the manifestation of the shape-memory effect. The physics of metals and metallography, 112 (5): 503-516.
Inaekyan K., Brailovski V., Prokoshkin S., Pushin V., Dubinskiy S., Sheremetyev V. 2015. Comparative study of structure formation and mechanical behavior of age-hardened Ti–Nb–Zr and Ti–Nb–Ta shape memory alloys. Materials Characterization, 103: 65-74.
Dubinskiy S., Brailovski V., Pokoshkin A., Pushin V., Inaekyan K., Sheremetyev V., Petrzhik M., Filonov M. 2013. Structure and properties of Ti-19.7 Nb-5.8 Ta shape memory alloy subjected to thermomechanical processing including aging. Journal of materials engineering and performance, 22 (9): 2656-2664.
Brailovski V., Prokoshkin S., Gauthier M., Inaekyan K., Dubinskiy S., Petrzhik M., Filonov. 2011. Bulk and porous metastable beta Ti–Nb–Zr (Ta) alloys for biomedical applications. Materials Science and Engineering: C, 31 (3): 643-657.
Takahashi E., Sakurai T., Watanabe S., Masahashi N., Hanada S. 2002. Effect of heat treatment and Sn content on superelasticity in biocompatible TiNbSn alloys. Materials Transactions, 43 (12): 2978-2983.
Fukui Y., Inamura T., Hosoda H., Wakashima K., Miyazaki S. 2004. Mechanical properties of a Ti-Nb-Al shape memory alloy. Materials Transactions, 45 (4): 1077-1082.
Kim J.I., Kim H.Y., Hosoda H., Miyazaki S. 2005. Shape memory behavior of Ti–22Nb–(0.5–2.0) O (at%) biomedical alloys. Materials transactions, 46 (4): 852-857.
Tahara M., Kim H.Y., Hosoda H., Miyazaki S. 2009. Shape memory effect and cyclic deformation behavior of Ti–Nb–N alloys. Functional Materials Letters, 2 (02): 79-82.
Al-Zain Y., Kim H.Y., Hosoda H., Nam T.H., Miyazaki S. 2010. Shape memory properties of Ti–Nb–Mo biomedical alloys. Acta Materialia, 58 (12): 4212-4223.
Kim H.Y., Oshika N., Kim J. Inamura T., Hosoda H., Miyazaki S. 2007. Martensitic transformation and superelasticity of Ti-Nb-Pt alloys. Materials transactions, 48 (3): 400-406.
Ping, D., Mitarai Y., Yin F. 2005. Microstructure and shape memory behavior of a Ti–30Nb–3Pd alloy. Scripta materialia, 52 (12): 1287-1291.
Kim H., Sasaki T., Okutsu K., Kim J., Inamura T., Hosoda H., Miyazaki S. 2006. Texture and shape memory behavior of Ti–22Nb–6Ta alloy. Acta Materialia, 54 (2): 423-433.
Bertrand E., Gloriant T., Gordin D.M., Vasiles u E., Drob P., Vasilescu C., Drob S.I. 2010. Synthesis and characterisation of a new superelastic Ti–25Ta–25Nb biomedical alloy. Journal of the mechanical behavior of biomedical materials, 3 (8): 559-564.
Hussein A.H., Gepreel H., Gouda M.K., Hefnawy A.M., Kandil S.H., 2016. Biocompatibility of new Ti–Nb–Ta base alloys. Materials Science and Engineering: C, 61: 574-578.
Qu, W.-T., Gong H., Wang J., Nie Y-S., Li Y. 2019. Martensitic transformation, shape memory effect and superelasticity of Ti–xZr–(30–x) Nb–4Ta alloys. Rare Metals, 38 (10): 965-970.
Kim H.Y., Miyazaki S. 2016. Several issues in the development of Ti–Nb-based shape memory alloys. Shape Memory and Superelasticity, 2 (4): 380-390.
Zarinejad M., Liu Y. 2010. Dependence of transformation temperatures of shape memory alloys on the number and concentration of valence electrons, Nova Science Publishers, Inc., New York, 339.