RESEARCH AND DEVELOPMENT OF NEW AND IMPROVED CUTTING TOOL MATERIALS.
Interim engineering progress rept. 13 Sep-31 Dec 65,
CARBORUNDUM CO NIAGARA FALLS N Y
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Results are presented of effort undertaken during the first quarter of Phase I of a program designed to develop new cutting tool materials for the machining of refractory metals for aerospace devices. Development is discussed of techniques for the fabrication of experimental cutting tool inserts from promising carbide, nitride, and boride systems as well as the results of cutting tests employing various experimental cutting tool compositions. Dense bodies having high modulus of rupture values were obtained through the hot pressing of tantalum diboride and tantalum diboride additive systems. Densification of tantalum monoboride and tantalum monoboride additive systems was, on the other hand, found to be difficult under the same conditions. A study of microstructure, phase relationships, and mechanical properties of the systems TaB and TaB2 with and without additives was performed. Detailed studies were performed on the effect of hot pressing parameters on the mechanical and chemical properties of two promising cutting tool compositions, 60 TaN - 40 ZrB2 and 50 TiB2 - 50 TaC. Cutting tests were performed on the turning of 4340 and D6AC steels employing TaN-ZrB2 cutting tools of various TaNZrB2 weight ratios. In both cases the 60 TaN - 40 ZrB2 composition tool showed optimum tool life. Author
- Machinery and Tools