The Effects of the Thermo-Mechanical Process Variables on the Microstructure, Mechanical Properties, and Recrystallization Behavior of the Commercially Pure Titanium

Document Type : Research Paper


1 Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz, 71946-84334, Iran

2 Department of Materials Engineering, Bu-Ali Sina University, Hamedan, 65178-38695, Iran


Commercial pure titanium sheets were thermo-mechanically treated to investigate the effects of the treatment variables on the microstructure, mechanical properties, and recrystallization behavior. The as-received sheets were initially cold-rolled up to different reduction percentages of 60%, 75%, and 90%. Then, the cold-rolled samples were annealed at different temperatures of 500°C-700°C, for various time ranges of 5 to 60 minutes. The evolution of the microstructure of the samples was studied using X-ray diffraction analysis and optical microscopy. The hardness of the 90% cold-rolled sample was about 82% higher than that of the as-received sheet. Increasing the time and temperature of the annealing process caused a decrease in the microhardness values of the samples. The recrystallization activation energy and Avrami’s exponent of the 90% cold-rolled sample were calculated as about 179 kJ/mol and 0.75, respectively. The results of the uniaxial tensile tests revealed that the cold-rolling process significantly improved the yield strength (YS) and ultimate tensile strength (UTS) of the specimens. In the case of the 90% cold-rolled sample, these values improved by about 160% and 117% with respect to the as-received metal, respectively. However, the elongation of the cold-rolled samples dropped sharply. Moreover, annealing had a positive effect on the elongation of the cold-rolled samples. The UTS and elongation percentage of the as-received sheet were 415 MPa and 36.4%, respectively. These values were varied to 558 MPa and 29.15% for the 90% cold-rolled sample annealed at 700°C for 1 h. To study the fracture behavior of the different samples, scanning electron microscopy (SEM) was used.


[1]    G. Lütjering, J. Williams, Titanium, Springer, Berlin, Heidelberg, 2003.
[2]    I. Polmear, D. StJohn, J.F. Nie, M. Qian, Light alloys: metallurgy of the light metals, Butterworth-Heinemann, 2017.
[3]    Y. Wang, W. He, N. Liu, A. Chapuis, B. Luan, Q. Liu, Effect of pre-annealing deformation on the recrystallized texture and grain boundary misorientation in commercial pure titanium, Materials Characterization, 136 (2018) 1-11.
[4]    F.J. Humphreys, M. Hatherly, Recrystallization and related annealing phenomena, Elsevier, Pergamon Press, Oxford, 2012.
[5]    G. Gottstein, Physical foundations of materials science, Springer-Verlag Berlin Heidelberg, 2004.
[6]    S. Panda, S.K. Sahoo, A. Dash, M. Bagwan, G. Kumar, S.C. Mishra, S. Suwas, Orientation dependent mechanical properties of commercially pure (cp) titanium, Materials Characterization, 98 (2014) 93-101.
[7]    S. Sinha, A. Ghosh, N.P. Gurao, Effect of initial orientation on the tensile properties of commercially pure titanium, Philosophical Magazine, 96(15) (2016) 1485-1508.
[8]    D. Kuhlmann-Wilsdorf, Theory of plastic deformation:-properties of low energy dislocation structures. Materials Science and Engineering: A, 113 (1989) 1-41. 
[9]    B. Bay, N. Hansen, D.A. Hughes, D. Kuhlmann-Wilsdorf, Overview no. 96 evolution of fcc deformation structures in polyslip. Acta Metallurgica et Materialia, 40(2) (1992) 205-219.
[10]  M.J. Phillippie, C. Esling, B. Hocheid, Role of twinning in texture development and in plastic deformation of hexagonal materials, Texture, Stress, and Microstructure, 7(4) (1988) 265-301.
[11]  Y.B. Chun, S.H. Yu, S.L. Semiatin, S.K. Hwang, Effect of deformation twinning on microstructure and texture evolution during cold rolling of CP-titanium, Materials Science and Engineering: A, 398(1-2) (2005) 209-219.
[12]  R.J. Contieri, M. Zanotello, R. Caram, Recrystallization and grain growth in highly cold worked CP-Titanium, Materials Science and Engineering: A, 527(16-17) (2010) 3994-4000.
[13]  T. Ungár, J. Gubicza, G. Ribárik, A. Borbély, Crystallite size distribution and dislocation structure determined by diffraction profile analysis: principles and practical application to cubic and hexagonal crystals. Journal of Applied Crystallography, 34(3) (2001) 298-310.
[14]  A. Fattah-alhosseini, M.K. Keshavarz, Y. Mazaheri, A.R. Ansari, M. Karimi, Strengthening mechanisms of nano-grained commercial pure titanium processed by accumulative roll bonding, Materials Science and Engineering: A, 693 (2017) 164-169.
[15]  H.S. Kim, W.J. Kim, Annealing effects on the corrosion resistance of ultrafine-grained pure titanium, Corrosion Science, 89 (2014) 331-337.
[16]  P. Sahu, M. De, S. Kajiwara, Microstructural characterization of stress-induced martensites evolved at low temperature in deformed powders of Fe-Mn-C alloys by the Rietveld method, Journal of Alloys and Compounds, 346(1-2) (2002) 158-169.
[17]  R.E. Smallman, Modern physical metallurgy, Elsevier, 2016.
[18]  A.O.F. Hayama, H.R.Z. Sandim, Annealing behavior of coarse-grained titanium deformed by cold rolling, Materials Science and Engineering: A, 418(1-2) (2006) 182-192.
[19]  S. Nourbaksh, T.D. O’Brien, Texture formation and transition in cold rolled titanium, Materials Science and Engineering, 100 (1988) 109-114.
[20]  S.V. Zherebtsov, G.S. Dyakonov, A.A. Salem, S.P. Malysheva, G.A. Salishchev, S.L. Semiatin, Evolution of grain and subgrain structure during cold rolling of commercial- purity titanium, Materials Science and Engineering: A, 528(9) (2011) 3474-3479.
[21]  H. Nasiri-Abarbekoh, A. Ekrami, A.A. Ziaei-Moayyed, M. Shohani, Effects of rolling reduction on mechanical properties anisotropy of commercially pure titanium, Materials & Design, 34 (2012) 268-274.
[22]  W. Pachla, M. Kulczyk, M. Sus-Ryszkowska, A. Mazur, K.J. Kurzydlowski, Nanocrystalline titanium produced by hydrostatic extrusion, Journal of Materials Processing Technology, 205(1-3) (2008) 173-182. 
[23]  A. Ghosh, A. Singh, N.P. Gurao, Effect of rolling mode and annealing temperature on microstructure and texture of commercially pure-titanium, Materials Characterization, 125 (2017) 83-93.
[24]  J. Burke, The kinetics of phase transformations in metals, Pergamon Press INC, 1965.
[25]  D.A. Porter, K.E. Easterling, Phase transformations in metals and alloys, Third Edition, CRC press, 2009.
[26]  X. Li, Y.L. Duan, G. F. Xu, X. Y. Peng, C. Dai, L. G. Zhang, Z. Li, EBSD characterization of twinning in cold-rolled CP-Ti, Materials Characterization, 84 (2013) 41-47.
[27]  L.I.U. Na, W.A.N.G. Ying, W.J. He, L.I.  Jun, A. Chapuis, B.F. Luan, L.I.U. Qing, Microstructure and textural evolution during cold rolling and annealing of commercially pure titanium sheet, Transactions of Nonferrous Metals Society of China, 28(6) (2018) 1123-1131.
[28]  D. Terada, S. Inoue, N. Tsuji, Microstructure and mechanical properties of commercial purity titanium severely deformed by ARB process, Journal of Materials Science, 42(5) (2007) 1673-1681.
[29]  G.E. Dieter, D. Bacon, Mechanical metallurgy, New York: McGraw-hill, 1976.
[30]  Y.M. Wang, E. Ma, M.W. Chen, Enhanced tensile ductility and toughness in nanostructured Cu, Applied Physics Letters, 80(13) (2002) 2395-2397.