Shear localization and chemical reaction in high-strain, high-strain-rate deformation of Ti–Si powder mixtures

• Published in: Acta materialia Vol. 46; no. 9; pp. 3033 - 3046
• Main Authors: Chen, H.C., LaSalvia, J.C., Nesterenko, V.F., Meyers, M.A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 22.05.1998; Elsevier Science
• Subjects: Applied sciences; Exact sciences and technology; Fibre reinforced metals; Metals. Metallurgy; Powder metallurgy. Composite materials; Production techniques; Shear; Silicon alloy; Theoretical study; Plastic deformation; Experimental study; Powder metallurgy; Titanium base alloys; Chemical reaction; High speed; Titanium; Thermodynamic analysis; Silicon; Shear band; Strain rate
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/S1359-6454(98)00016-0

Ti–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 sufficiently high strains ( γ∼10), and propagation of the reaction through the entire specimen at higher strains ( γ∼20–40). This study demonstrates that temperature increases in shear localization regions can initiate chemical reaction inside a reactive powder mixture. The shear band spacing was ∼0.6–1 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 s −1 at 1685 K.