Comparison between Wrought and EBM Ti6Al4V Machinability Characteristics

Abstract

Electron Beam Melting (EBM) is attracting large interest among the manufacturers of surgical implants as a near-net shape technology. Titanium alloy Ti6Al4V is widely used in the biomedical field thanks to its high biocompatibility, corrosion resistance and mechanical properties. The chemistry and microstructural features of EBM Ti6Al4V indicate lower machinability in comparison with wrought Ti6Al4V. Aim of the paper is to present a comparison between the machinability of wrought and EBM Ti6Al4V in semi-finishing external turning, by quantifying the effects of the cutting speed and the feed rate. Tool wear, surface integrity, chip morphology and microstructural analysis have been used to compare and assess the machinability of Ti6Al4V delivered in the two conditions.

Analysis of tool wear in cryogenic machining of additive manufactured Ti6Al4V alloy

“…While the influence of the EBM process parameters on the part obtainable characteristics have been quite extensively studied [1,2], in literature there are very few works concerning experimental investigations on the machinability of EBM Ti alloys, and neither an exhaustive discussion about tool wear degradation can be found. Bordin et al [3] compared the machinability of EBM and wrought Ti6Al4V in semi-finishing external turning, when using a PVD coated tungsten carbide insert in conventional flood cooling conditions. The EBM Ti6Al4V resulted to be more difficult to machine than the wrought alloy for all the tested cutting conditions resulting in a worse surface integrity, which was evaluated in terms of surface roughness and topography.…”

Environmentally clean micromilling of electron beam melted Ti6Al4V

“…micro-machining is not in agreement with what observed in cryogenic conventional machining (Bordin et al, 2014). In Fig.…”

“…The investigation of the surface integrity of AM titanium alloys subjected to machining operations is therefore mandatory to guarantee the parts functional performances (Jawahir et al, 2011;Kaynak et al, 2014;Ulutan and Ozel, 2011). However, despite the growing interest in AM parts, scarce records can be found in literature addressing this topic (Bordin et al, 2014), only M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT related to conventional machining processes at macro-level, still leaving the field of micro-machining of AM parts completely unexplored, whereas micro-cutting of wrought Ti6Al4V parts has been recently addressed (Özel et al, 2011).…”

Metallurgical and Machinability Characteristics of Wrought and Selective Laser Melted Ti-6Al-4V

“…Poor thermal conductivity of titanium alloys combined with their high chemical reactivity leads to high wear rate of cutting tools [13][14][15]. Only very few papers discussing the machinability of additive manufactured titanium alloys are available [16][17][18][19][20][21][22]. Oyelola et al [16] investigated the machining behaviour and surface integrity of Ti-6Al-4V components produced by direct metal deposition additive manufacturing technology.…”

“…Montevecchi et al [17] investigated the cutting force behaviour of two additive manufacturing technologies such as laser deposition and wire arc additive manufacturing. Bordin et al [20] compared the machinability of wrought and electron beam melted Ti-6Al-4V during semifinish turning. Also recently, Bordin et al [21] evaluated the tool wear mechanisms arising when semifinish turning EBM Ti-6Al-4V under dry and cryogenic conditions in an attempt to improve the machinability of additive manufactured components.…”