Chip and built-up edge formation in the machining of in situ Al4C3–Al composite

Abstract

Abstract As a consequence of widening range of applications of metal-matrix composites (MMCs), the machining of these materials has become a very important subject for research. This paper describes a study of chip formation during the machining of MMCs produced by the mechanical alloying (MA) technique. Aluminium based composite which contained various amounts of in situ Al 4 C 3 particles, depending on MA time, were produced. Scanning electron microscopy and mechanical properties of the block samples produced by powder metallurgy technique were investigated. The chip-formation mechanism in machining of these MMCs at various cutting speeds has, therefore, been investigated by using a quick-stop device. During the machining of MMCs, elemental and arc chips formations were observed. Increasing the hardness due to high volume fraction of Al 4 C 3 in the matrix resulted in a decrease in the formation of built-up edge but increased the surface quality at high cutting speeds. It was concluded that the effect of Al 4 C 3 on the crack formation in shear plane, shortened the chip contact length and the chip segment thickness.