Optimization of Mechanical Machining for Heat-Resistance Ta-W Alloy by Using Orthogonal Cutting Method

Abstract

Tantalum and tantalum alloys, which have superior thermal properties, including a high melting temperature, low specific heat, low thermal conductivity, and high density, are promising candidates for high-performance parts exposed to high temperatures and hazardous environments in aerospace, defense, and other industries. However, those alloys are hard to cut and mechanically machine, and the poor machinability of tantalum alloys has precluded their wide use. This study investigates mechanisms for cutting Ta-10%W alloys using orthogonal cutting methods for precision part manufacturing. During orthogonal cutting processes, the cutting forces are increased dramatically because of the surface folding phenomenon of Ta-W alloys. As a result of experiments and simulation calculations, the tool's rake angle and depth of cut are critical parameters for controlling the cutting shear angle, which makes a significant difference in chip thicknesses and surface folding phenomenon. Based on the results, about 12 degrees of cutting shear angle is suitable for the mechanical machining of a Ta-W alloy. Additionally, cutting speed may be one of the critical parameters to consider for changing the mechanical responses of Ta-W alloys. With this perspective, the mechanical properties of Ta-W alloys at high strain rates seem to be an important factor in orthogonal cutting. Based on these results, the cutting mechanisms and optimal cutting parameters for Ta-W alloys are discussed.