Experimental Investigation of Modes II and III Fatigue Crack Growth in Unalloyed Titanium

Abstract:

The study is focused on finding and describing microscopic paths of modes II and III cracks in commercially pure α-titanium (hcp structure). Experiments were done on cylindrical bars with a circumferential cracked notch loaded in shear (modes II, III and II + III) and torsion (mode III). Fractography analysis showed that the crack growth was crystallography-controlled and the deflection and twisting angles of crack propagation direction (with respect to the shear plane) were relatively high. This behavior is a mixture of previously observed morphology in ARMCO iron (bcc) and austenitic steel (fcc). It can be understood in terms of a number of available slip systems in bcc, fcc and hcp lattices.

• Periodical: Key Engineering Materials (Volumes 592-593)
• Pages: 797-800
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.592-593.797
• Online since: November 2013
• Authors: Tomáš Vojtek*, Jaroslav Pokluda
• Keywords: Mode I Branching, Shear Fatigue Cracks, Stereophotogrammetry, Titanium

References

[1] L.P. Pook: Crack Paths, Wit Press, Southampton-Boston (2002).

[2] S. Suresh: Fatigue of Materials, Cambridge University Press (1998).

[3] J. Pokluda and P. Šandera: Micromechanisms of Fracture and Fatigue, Springer (2010).

[4] Y. Murakami: Metal Fatigue: Effects of Small Defects and Nonmetallic Inclusions, Elsevier (2002).

[5] T. Vojtek, R. Pippan, A. Hohenwarter, L. Holáň and J. Pokluda: Acta Materialia Vol. 61 (2013), p.4625.

DOI: 10.1016/j.actamat.2013.04.033

[6] T. Vojtek, J. Pokluda, A. Hohenwarter and R. Pippan: Engineering Fracture Mechanics Vol. 108 (2013), p.285.

DOI: 10.1016/j.engfracmech.2013.02.022

[7] C.B. Parker: Encyclopaedia of Physics, second ed., McGraw Hill; (1994).