Studies on conventional cutting of intermetallic nickel and titanium aluminides

Abstract

Owing to the high percentage of covalent bonds, intermetallic nickel and titanium aluminides have specific physical and chemical characteristics that predestine them for components under high thermal and mechanical load. However, the relatively low ductility and thermal conductivity at room temperature, linked to high tensile strength, impede the machining with geometrically defined cutting edges in series production. The conventional machining process is characterized by microcrack formation at the component surface. One possible way is to warm up the intermetallic alloys locally above the quasi-brittle-ductile transition temperature by the interaction of the workpiece material and the tool. The subjects of investigation were the influences of feed rate and cutting speed on the tool-face temperature and cutting force as well as on the chip formation and fringe-area formation during longitudinal cylindrical turning. The experiments were carried out with intermetallic nickel and titanium aluminides in an as-cast and extruded state. The goal was to elaborate the technological basic knowledge for a damage-minimized and productive machining of intermetallic aluminides with geometrically defined cutting edges.