SHEAR LOCALIZATION AND CHEMICAL REACTION IN HIGH-STRAIN, HIGH-STRAIN-RATE DEFORMATION OF Ti±Si POWDER MIXTURES
نویسندگان
چکیده
ÐTi±Si mixtures were subjected to high-strain-rate deformation at a pressure below the threshold for shock-wave initiation. Whereas the collapse of interparticle pores did not initiate reaction, regions of localized macro-deformation initiated reaction inside shear bands at suciently high strains (g010), and propagation of the reaction through the entire specimen at higher strains (g020±40). This study demonstrates that temperature increases in shear localization regions can initiate chemical reaction inside a reactive powder mixture. The shear band spacing was 00.6±1 mm. Thermodynamic and kinetic calculations yield the reaction rate outside the shear bands, in the homogeneously deformed material, which has a maximum value of 20 sÿ1 at 1685 K. # 1998 Acta Metallurgica Inc.
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