Analytical Electron Microscopy of (W,Ti)C

Abstract

Addition of titanium to tungsten carbide changes its structure from hexagonal to NaCl type in the single phase region of the W-Ti-C ternary. This results in a change of the slip systems active during deformation. It Is thus possible to improve the mechanical properties of WC (especially toughness) by the alloying addition of Ti. The purpose of this study is to identify the appropriate deformation mechanisms, using TEM techniques. The present report deals with investigations on deformed and undeformed single phase ternary carbides. The bulk (W,Ti)C samples were obtained by arc melting presintered pellets of mechanically mixed WC and TiC powders with a nominal composition of 22.5% W, 32.5% Ti, and 45% C (atomic). Three millimeter dia. discs of 100 μm thickness were obtained from these samples by spark cutting and further mechanical grinding. The deformation was introduced by creating a square array of micro-indentations. The discs were then ion-beam thinned.