13th International Conference on Fracture June 16–21, 2013, Beijing, China -6- 4. Discussion Void linkage occurs prematurely in the magnesium materials tested. The premature linkage is associated with the failure of grain and twin boundaries. Both extension and compression twins have been characterized and contribute to the final failure. The weak correlation between the void fraction and void orientation on failure is a direct consequence of the fact that void linkage is not entirely driven by plasticity. Tomography tests have shown that the failure of the materials is quite complex and 3D techniques must be used to determine where the first failure site occurs. 5. References [1] Barnett, M.R., Twinning and the ductility of magnesium alloys: Part I: “Tension” twins. Materials Science and Engineering: A, 2007. 464(1–2): p. 1-7. [2] Weck, A. and D.S. Wilkinson, Experimental investigation of void coalescence in metallic sheets containing laser drilled holes. Acta Materialia, 2008. 56(8): p. 1774-1784. [3] Weck, A., et al., Femtosecond laser-based fabrication of a new model material to study fracture. Applied Physics A, 2007. 86(1): p. 55-61. [4] Puttick, K.E., Ductile fracture in metals. Philosophical Magazine, 1959. 4(44): p. 964-969. [5] Hosokawa, A., et al., Effect of triaxiality on void growth and coalescence in model materials investigated by X-ray tomography. Acta Materialia, 2012. 60(6–7): p. 2829-2839. [6] Salvo, L., et al., X-ray micro-tomography an attractive characterisation technique in materials science. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2003. 200(0): p. 273-286.
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