Tensile Properties and Dislocation Strengthening of Commercial Pure Titanium Processed by Equal-Channel Angular Pressing at Liquid Nitrogen Temperature

Abstract:

Equal channel angular pressing (ECAP) of a quenched commercial pure titanium (CP-Ti) (grade 2) has been successfully performed at liquid nitrogen temperature with an imposed equivalent strain of about ∼0.5, and its microstructures, tensile properties and dislocation strengthening were investigated. High-resolution transmission electron microscopy (HRTEM) shows that the ECAPed CP-Ti presented a microstructure containing lattice distortions, dislocations, stacking defects and deformation twins. Tensile tests indicate that the ECAPed CP-Ti had yield strength of ~700 MPa (40 % higher than that of the unECAPed CP-Ti) and a high level of tensile ductility (~28%). X-ray diffractometer (XRD) data indicate that the ECAP processing not only broaden the XRD peaks significantly but also decreased texture considerably. The theoretical analysis by using Taylor equation based on the coherent diffraction domain size and the lattice micro-strain obtained from XRD line broadening analysis illustrates that ECAP-resulted dislocation made a strengthening contribution of about ~35.1 %.

• Periodical: Materials Science Forum (Volume 682)
• Pages: 171-176
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.682.171
• Online since: March 2011
• Authors: Xiao Nong Cheng, Hong Xing Xu, Xiao Jing Xu, Zeng Lei Zhang
• Keywords: Equal-Channel Angular Pressing (ECAP), Strengthening Mechanisms, Titanium

References

[1] R.Z. Valiev, R.K. Islamgaliev and I.V. Alexandrov: Prog. Mater. Sci. Vol. 45(2) (2000), p.102.

[2] R.Z. Valiev and T.G. Langdon: Prog. Mater. Sci. Vol. 51(7) (2006), p.881.

[3] T.G. Langdon: Mater. Sci. Eng. A Vol. 462(1-2) (2007), p.3.

[4] X.J. Xu, H.H. Shao, J. Ch. Gao, K.M. Chen and X.N. Cheng: Mater. Sci. Eng. A Vol. 493(1-2) (2008), p.195.

[5] H.J. Rack and J.I. Qazi: Mater. Sci. Eng. C Vol. 26(8) (2006), p.1269.

[6] V. Latysh, Gy. Krallics, I. Alexandrov and A. Fodor: Curr. Appl. Phys. Vol. 6(2) (2006), p.262.

[7] Y.T. Zhu, T.C. Lowe and T.G. Langdon: Scripta Mater. Vol. 51(8) (2004), p.825.

[8] X.J. Xu, X.F. Zhang, J.Q. Cao, K.M. Chen and L. Pan: Proceedings of the International Conference on Integration and Commercialization of Micro and Nanosystems Vol. A (2007), p.669.

[9] X.J. Xu, J.Q. Cao, Y.J. Jiang, S.X. Luo and X.F. Zhang: Journal of Functional Materials Vol. 37 (s) (2006), p.657(in Chinese).

[10] K.M. Youssef, R.O. Scattergood, K.L. Murty and C.C. Koch: Scripta Mater. Vol. 54 (2) (2006), p.251.

[11] Y. H. Zhao, X. Z. Liao, Z. Jin, R. Z. Valiev and Y. T. Zhu: Acta Mater. Vol. 52 (15) (2004), p.4589.

[12] Y.G. Ko, D. H. Shin, K. Park and Ch. S. Lee: Scripta Mater. Vol. 54 (2006), p.1785.

[13] N. Krasilnikov, W. Lojkowski, Z. Pakiela and R. Valiev: Mater. Sci. Eng. A Vol. 397(1-2) (2005), p.330.

[14] X.J. Xu, J.Q. Cao, X.N. Cheng and J.P. Mo: Trans. Nonferrous Met. Soc. China Vol. 16(s 3) (2006), p.1541.