STRUCTURE AND PROPERTIES OF TITANIUM-ALLOY LTS WITH AN ELEVATED CARBON CONTENT

1. The value of the average degree of directionality of bonds in a system, {Mathematical expression}, is highly sensitive to structure, and may be recommended as an integral criterion for the selection of microalloying additions for not only titanium based systems, but also for other metallic systems. 2. Adding yttrium (0.01%) to an LTS alloy containing an elevated carbon concentration (0.2-0.25%) produces a redistribution of carbon, increasing its solubility in the α- and β-phases. As a result the titanium carbide, TiC (or δ-phase), precipitates during solidification after ESR and microalloying in the form of finely dispersed spherical inclusions, uniformly distributed within the primary β-grains. Consequently, the mechanical properties of the LTS alloy, and the impact toughness in particular, are increased to levels which satisfy the requirements for articles cast from this alloy. © 1992 Plenum Publishing Corporation.