In situ observation of micro-cutting of Al-Si alloy by using scanning electron microscope

Abstract

This paper describes an experimental investigation of a micro-cutting to make clear the severe tool wear mechanism in hypereutectic Al-20%Si alloy. Tool wear of carbide tool is mainly induced by the mechanical scratching action with crushed primary Si particles. In situ observation by using SEM micro-cutting system is found to be very successful for the clarification of the interaction between crushed primary Si particles and a cutting edge of tool. Summary of the results are shown below. (1) Primary Si particles are crushed and/or fine grained in the shearing zone. A part of them are observed to collide directly with a cutting edge of tool by following the micro-cutting. This appears to be a cause of severe tool wear in turning of this alloy. (2) The direction of primary cracks in primary Si particles almost agree with those of principal stress under a compressive value by the elastic stress analysis.