Issue 30

V. Di Cocco et alii, Frattura ed Integrità Strutturale, 30 (2014) 454-461; DOI: 10.3221/IGF-ESIS.30.55 461 3) for R = 0.1, corresponding to “Stage 4”, a stress induced microstructure modification is obtained as a consequence of the crack tip stress field, with the consequent initiation of very short microcracks; 4) For R=0.5, no microcracks are observed ahead of the crack tip; 5) For R=0.5, Secondary cracks do not join again the main crack. R EFERENCES [1] Dong, Y., Boming, Z., Jun, L., A changeable aerofoil actuated by shape memory alloy springs, Materials Science and Engineering A, 485 (2008) 243–250. [2] Otsuka, K., Ren, X., Physical metallurgy of Ti–Ni-based shape memory alloys, Progress in Materials Science (2005) 511. [3] Chen, B., Liang, C., Fu, D., Pitting corrosion of Cu-Zn-Al shape memory alloy in simulated uterine fluid, J. Mater. Sci. Technology, 21(2) (2005) 226-230.3 [4] Liu, Y., Tan, G.S., Formation of interfacial voids in cast and micro-grained γ′-Ni3Al during high temperature oxidation, Intermetallics (2000) 8 1385-1391.4 [5] Suzuki, T., Kojima, R., Fujii, Y., Nagasawa, A., Acta Metall., 37 (1) (1989) 163–168.3 [6] Asanovic, V., Delijic, K., Jaukovic, N., A study of transformation of β-phase in Cu-Zn –Al shape memory alloys, Scripta Materialia, 58 (2008) 599-601.7 [7] Kayali, N., Ozgen, S., Adiguzel, O., Strain effects on the macroscopic behaviour and martensite morphology in shape-memory CuZnAl alloys, Journal of Materials Processing Technology, 101 (2000) 245-249.6 [8] Zhang, J.X., Zheng, Y.F., Zhao, L.C., The structure and mobility of intervariant boundaries in 18R martensite in a Cu-Zn-Al alloy, Acta mater., 47(7) (1999) 2125-2141. [9] Di Cocco, V., Iacoviello, F., Tomassi, L., Rossi, A., Natali, S.,Volpe, V., Crack path in a Zn-Cu-Al PE alloy under uniaxial load, Convegno Nazionale IGF XXII, Roma, Italia, 1-3 Luglio 2013, 255-261, Acta Fracturae ISSN 2281- 1443. [10] Rapacioli, R., Ahlers, M., Ordering in ternary β CuZnAl alloys, Scripta Met., 11 (1977) 1147-1150. [11] Chandrasekaran, M., Cooreman, L., Yan Humbeek, J., Delaey, L., Martensitic transformation in Cu-Zn-Al: changer in transformation entropy due to post-quench ageing in the β or martensitic condition, Scripta Met., 23 (1989) 237-239. [12] Wang, T.M., Wang, B.Y., Feng, B.X., Liu, C.L., Jiang, B.H., Xu, Z.Y., the recovery behavior of quenched-in vacancies in Cu-Zn-Al alloy, Phys. Stat. Sol., 114 (1989) 451.