Performance and wear mechanisms of uncoated, tialn, and altin-coated carbide tools in high-speed drilling of al-si alloy

Abstract

Owning to the extremely abrasive silicon particles, low melting point of aluminum, and its susceptibility to adhere to the tool, high-speed drilling of aluminum alloys containing high silicon content becomes a challenging operation. Hence, the understanding of the tool wear mechanisms is essential in order to develop and select the efficient tool material. This paper reports on the investigation of performance and wear mechanism of uncoated and TiAlN and AlTiN-coated tools when high-speed drilling of Al-Si (A383) alloy. Drilling tests were conducted at various cutting parameters, while thrust forces were measured using a dynamometer. The wear mechanisms that contributed to the drill failure were assessed by analyzing the worn cutting edge and drill bit cross section; and by employing scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Results showed that feed rate has the highest effect on the primary wear stage; and flank wear at the outer cutting edge found to be dominant failure mode for all tools. Moreover, it is found that plastic deformation, diffusion, attrition, abrasion, and fracture are the main operating tool wear mechanisms. The longest tool life was recorded for AlTiN-coated tool, but more adhesion of Al was observed on this tool surface. At the end, TiAlN-coated drill was proposed as the tool with the best performance among the tool materials used in this study.