Properties of WC-TiC-10%Co(β-10%Co) Two Phase Alloys in Connection with Carbon Content of Alloys

Abstract

The relation between the basic properties of typical WC-β-Co three phase alloys and the carbon content was already reported. In this report, the researches on the same subject have been carried out mainly on β-Co two phase alloys. The cobalt content in the alloys was mainly kept at 10wt%, and the titanium carbide content in carbides was 30%, 50% or 25%. The carbon content was strictly controlled. Samples were vacuum-sintered at 1430°C for 1 hr.Main results obtained were as follows ;(1) The lattice parameter of γ-phase varied with the increase of carbon content of alloys, from about 3.593A to 3.560A and from about 3.605A to 3.560A in 30% and 50% titanium carbide alloys, respectively. (2) The lattice parameter of γ-phase in 25% titanium carbide alloy (containing a small amount of WC phase) was between that of β-Co two phase alloy and that of typical WC-β-Co three phase alloy. (3) W dissolved much more than Ti.in the γ-phase in the low carbon alloys. (4) The lattice parameter of β-phase varied with the increase of carbon content of the alloys, from about 4.314A to 4.321A and from about 4.318A to 4.324A in 30%b and 50% titanium carbide alloys, respectively. (5) The change in carbon content of β-phase resulted in the extension of (β+γ) two phase range. Continued from (WC+β+γ) three phase range, the width of the range increased with the increase in the titanium carbide content. (6) Phenomena mentioned above could be explained by the Ti-W-C three phase diagram. (7) Other properties showed regular changes in the phase range.