Contents lists available at ScienceDirect Wear journal homepage: www.elsevier.com/locate/wear Investigation of surface topology in ball nose end milling process of Inconel 718 M.S. Kasim a, ⁎ , M.S.A. Hafz a , J.A. Ghani b , C.H.C. Haron b , R. Izamshah a , S.A. Sundi c , S.B. Mohamed d , I.S. Othman a a Fakulti Kejuruteraan Pembuatan, Universiti Teknikal Malaysia Melaka, Durian Tunggal, Malaysia b Faculty of Engineering and the Build Environment, Universiti Kebangsaan Malaysia, Selangor, Malaysia c Fakulti Teknologi Kejuruteraan, Universiti Teknikal Malaysia Melaka, Durian Tunggal, Malaysia d Faculty of Innovative Design and Technology, Universiti Sultan Zainal Abidin, Terengganu, Malaysia ARTICLEINFO Keywords: Ball nose end milling Inconel 718 Surface topology Notch wear High speed machining Third body abrasion ABSTRACT Inconel 718 known as hard-to-cut material due to its superior mechanical properties; high creep resistance, high fatigue strength, and able to withstand at elevated temperature which remains as challenge to possesses a lower surface roughness (Ra) during machining. The surface topology indicates the integrity of the machined parts. ThequalityoftheInconel718surfaceduringendmillingprocesswasinvestigated.Theexperimentsinvolvedthe use of PVD coated with TiAlN/ AlCrN ball nose tungsten carbide with varying of cutting speeds (Vc) ranging between 100 and 140m/min, a feed rate (fz) of 0.1–0.2mm/tooth, and an axial depth of cut (DoC) of 0.5–1.0mm. The efects of the width of cut (WoC) between 0.2 and 1.8mm were carried out. Due to the profle of the milled surface is complex; some variations in gap distance on the spiral profle were detected. The cutting pathareatobefoundthat,thenewcutisoverlappedwhichgenerateanewsurfaceroughnessbyeliminatingthe previous cut thus the non-uniform feed marks being created on the machined surface. The surface roughness measured in feed direction was found to be lowered than pick a direction. Furthermore it was found that the WoC are causes the variation in Ra. During machining at low feed rates, the phenomenon of carbide particles was observed which results third body abrasion of machined surface. The particles are then trapped between the fragmentsandtearsurfaceoftheworkpiece,thusincreasesthesurfaceroughness.Basedontheinteractionefect of WoC and fz, it can be concluded that the feed rate efects on the quality of machined surface whilst WoC controls Ra variation. 1. Introduction Aerospace industry is the highly upcoming sector with new mate- rials was chosen for the best mechanical properties. The nickel based superalloy,Inconel718exhibitsbestcharacteristicmakeitthechoiceof material with its outstanding characteristics and for the aerospace in- dustry as reported. Inconel 718 ofers high strength, high toughness, high temperature capability, creep resistance, high fatigue endurance and environment degradation resistance [1,2]. However, the high alloy content and high strength at extreme temperatures of Inconel 718 that resist plastic deformation during machining, leads to rapid strain hardening [3]. These conditions lead to the formation of sub-surface residualstressesatthemachinedsurface,thatcausesstraindamageand dimensional instability [4]. Trent and Wright [5] reported that the ef- fect of sub-surface strain damage negatively impacts the fatigue life which signifcantly reduce the number of cycles to component failure. This is agreed and reported by Hardy et al. [6] as well. Fabrication of aerospace parts requires high accuracy with good surface fnish. Surface roughness is a geometrical measure of surface quality and main criteria for the acceptance of the fnished component. Literatures reported several strategies of milling cutting process that associated with surface integrity, namely the optimization of cutting parameters [7–9], tool performance [10], tool geometry [11,12], cut- ting force [13], chip formation [14], workpiece rigidity [15], and the lubrication and cooling systems [16,17]. In the machining of Inconel 718, the common surface anomalies identifed were material drags, white layers, scoring and plucks [6,18,19]. Thakur and his team [20] revealed that poor surface roughness was incorporatived with the presence of hard carbide particles that abrade the machined surface. Surface roughness is very critical for the machining due to the https://doi.org/10.1016/j.wear.2018.12.076 Received 2 September 2018; Received in revised form 20 December 2018; Accepted 24 December 2018 ⁎ Corresponding author. E-mail address: shahir@utem.edu.my (M.S. Kasim). Wear 426–427 (2019) 1318–1326 0043-1648/ © 2018 Elsevier B.V. All rights reserved. T