Ultra-high-speed exploding properties of Ti-6Al-4V alloy having equiaxed and bimodal microstructures
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Fig. 2—(Continued). Micrographs for T91 and CSLE T91 showing (a) and (b) grain size, (c) and (d) carbide size and location, and (e) and (f ) population fraction of grain boundary misorientation relation between misorientation angle and fraction of various boundaries (3 boundaries correspond to an angle of 30 deg). 17. D.G. Brandon: Acta Metall., 1966, vol. 14, pp. 1479-84. 18. D.C. Crawford and G.S. Was: Metall. Trans. A, 1992, vol. 23A, pp. 1195-1206. 19. G.S. Was, V. Thaveeprungsriporn, and D.C. Crawford: J. Mater., 1998, vol. 50 (2), pp. 44-49. 20. B. Alexandreanu, B.M. Capell, and G.S. Was: Mater. Sci. Eng. A, 2001, vol. 300, pp. 94-105.
Ultra-High-Speed Exploding Properties of Ti-6Al-4V Alloy Having Equiaxed and Bimodal Microstructures DONG-GEUN LEE, YOU HWAN LEE, SUNGHAK LEE, CHONG SOO LEE, JOON-HONG CHOI, and SUN-MOO HUR Unlike in typical cases in which deformation and fracture proceed gradually when static loading is applied to a material, studies on dynamic deformation and fracture have been
DONG-GEUN LEE, Postdoctoral Research Associate, and YOU HWAN LEE, Research Assistant, are with the Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang, 790–784, Korea. Contact e-mail: [email protected] SUNGHAK LEE and CHONG SOO LEE, Professors, Center for Advanced Aerospace Materials, Pohang University of Science and Technology, are jointly appointed with the Materials Science and Engineering Department, Pohang University of Science and Technology. JOON-HONG CHOI, Senior Researcher, and SUN-MOO HUR, Principal Researcher, are with the Agency for Defense Development, Daejon, 305-600, Korea. Manuscript submitted May 22, 2003. METALLURGICAL AND MATERIALS TRANSACTIONS A
made to predict ballistic performance and impact resistance from the extent of the adiabatic shear band formation. Adiabatic shear bands are generated by strain localization and temperature rise due to plastic instability at impacted regions, and work as a critical factor abruptly reducing impact resistance.[1–9] Thus, research on how to remove or prevent the formation of adiabatic shear bands is demanded for the development of Ti-6Al-4V alloy for armor plates. In the present study, an exploding bridge wire (EBW) test was conducted on Ti-6Al-4V alloy having equiaxed and bimodal microstructures at a strain rate of about 105/s, which is similar to the strain rate under ballistic impact test. From the test, strength at the Hugoniot elastic limit (HEL) and dynamic fracture strength (spall strength) were measured, and subsequently, ballistic mass efficiency was predicted on the basis of the concept of particle velocity and impedance. Material used in this study was a Ti-6Al-4V alloy plate (thickness: 20 mm) manufactured at Allegheny Ludlum Co. (Pittsburgh, PA) and its chemical composition was 6.36Al3.83V-0.22Fe-0.180-0.02C-0.01N-0.006H-Ti (wt pct). This alloy was subjected to different heat treatments to obtain equiaxed and bimodal. The equiaxed was obtained by holding a
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