Machinability of titanium alloy (Ti’6Al’4V) by abrasive waterjets

Abstract

Titanium alloy is known as one of the di cult-to-machine materials using conventional machining processes, although it has superior formability. In the present study, a widely used aircraft structural titanium alloy (Ti±6Al±4V) was machined with an abrasive waterjet (AWJ) to investigate its machinability under varying cutting conditions. Machinability was evaluated in terms of kerf geometry, cut surface quality and microstructural integrity. Quality of the machined surface and microstructure features were examined using surface pro®lometry, scanning electron microscopy and energy dispersive X-ray (EDX) analysis. The surface roughness was ranged several micrometres near the jet entrance region and was observed to increase at the jet exit of the workpiece. Scanning electron microscopy (SEM) analysis of the surface microstructure revealed that the mechanism of material removal was a combination of scooping induced ductile shear and ploughing actions of the abrasive particles. EDX analysis showed garnet particle embedment in titanium throughout the cutting depth, and the particle size was estimated to be several tens of micrometres.

An experimental study on abrasive waterjet cutting of CFRP/Ti6Al4V stacks for drilling operations

“…Pahuja et al [11] studied the machining of hybrid titanium/graphite composite laminates by AWJ and found that surface roughness is higher for small arc tool paths than for large arcs or straight cuts. In addition, they found different material removal mechanisms for different material phases and obtained similar conclusions as Seo et al [12] and Arola and Ramulu [13,14]: the titanium is cut by ductile shearing, abrasive ploughing, and scratching action; the matrix material is cut by shearing and plastic deformation; and the fibers are cut by microchipping, brittle fracture, and bending failure. Arola and Ramulu also found deformation and subsurface hardening in the AWJ machining of Ti6Al4V [15] and found three cutting regions including initial damage region (IDR), smooth cutting region (SCR), and rough cutting region (RCR) in both graphite/epoxy composites [13,14] and Ti6Al4V [15].…”

“…Despite the small amount of articles studying the drilling process by AWJ technology [9,10] and the machining of hybrid titanium/graphite composite laminates [11], it is possible to find several references which have done the characterization of Ti6Al4V and CFRP materials separately [12][13][14][15][16][17][18][19]. Escobar-Palafox et al [9] and Hussein Mohammed Ali Ibraheem et al [10] developed mathematical models for predicting the quality of the hole as a function of process parameters based on statistical analysis.…”

Effect of traverse speed on abrasive waterjet machining of Ti–6Al–4V alloy

“…1 shows cutting surface view of samples machined at traverse speed of 60-200 mm/min, respectively. Microstructural evaluation of the cutting surfaces of samples revealed three distinct zones which were identified as: (1) a initial damage region (IDR), which is cutting zone at shallow angles of attack; (2) a smooth cutting region (SCR), which is cutting zone at large angles of attack; (3) a rough cutting region (RCR), which is the jet upward deflection zone [17,18]. The surface morphology in different regions of cutting surface is generated from the instantaneous penetration of abrasive waterjet.…”

“…A high-speed waterjet transfers kinetic energy to the abrasive particles and the mixture impinges on to the workpiece [10]. The material removal rate is dependent on the abrasive attack and mechanical properties of target metal.…”

An experimental study of abrasive waterjet machining of Ti-6Al-4V

“…It has been regarded as a key enabling technology for machining parts made of difficult-to-cut materials. Seo et al [8] conducted an experiment to investigate the machinability of Ti-6Al-4V using AWJ. They evaluated the kerf geometry, cut surface quality and microstructural integrity, and reported that optimum cutting parameters are function of traverse speed, pump pressure, stand-off distance and garnet size.…”