Abstract
Microcutting of AFRM (Alumina Fiber Reinforced Metal) are performed with SEM direct observation method. The purpose of this study is to make clear the cutting mechanism of AFRM and the fracture of fibers at the plastic deformation zone of the orthogonal microcutting. Since AFRM shows an obvious anisotropic strength depending on the direction of fiber axes, cutting direction are classified by the fiber angle. Summary of the results are shown below. (1) The fracture of fibers in microcutting with carbide tool are caused by shearing, tensile and bending forces. (2) In fiber angle 30° and 60°, the direct collision of fibers with cutting edge of tool were observed with high frequency. In these cases, fibers were fractured by the shearing force. (3) In another fiber angles, fibers were fractured by the bending forces after the severe bending deformation. The amount of deformation in fibers became larger in the case of fiber angle 90° and 120° with an extensive overcut. This enhances difficulties in the exhaust of chip and worsens the surface finish. (4) The deformation zone of the orthogonal microcutting with diamond tool was found to decrease by approximately one-half comparing with carbide tool. This can be attributed to the low friction coefficient between the rake face and a sharp edge of the cutting tool. (5) Four typical cutting mechanism have been proposed by the results of the direct observation of microcutting of AFRM.
