Creep feed grinding of gamma titanium aluminide and burn resistant titanium alloys using SiC abrasive

Following a brief introduction to titanium alloys and their machinability, the cutting performance of a gamma titanium aluminide intermetallic (gamma-TiA1) alloy: Ti-45A1-8Nb-0.2C wt% and a burn resistant titanium (BuRTi) alloy: Ti-25V-15Cr-2A1-0.2C wt%, is compared with creep feed grinding using SiC abrasive. The work utilised 2 separate L9 Taguchi fractional factorial arrays. Typically G-ratios were a factor of similar to 10 x greater for gamma-TiA1 than BuRTi, with on average similar to 10% lower maximum power and similar to 25% lower maximum specific energy for the gamma-TiA1 alloy. A combination of a moderately high wheel speed: 35 m/s, low depth of cut: 1.25 mm and low feed rate: 150mm/min, produced the lowest average workpiece surface roughness (Ra similar to 1.4 mu m). Workpiece surface integrity evaluation indicated that with lower operating parameter levels, in particular a wheel speed of 15 m/s, surfaces free of burn and cracks could be produced, while at higher wheel speeds: 35m/s, extensive workpiece surface burn was evident, with the gamma-TiA1 alloy suffering extensive cracking. Microhardness measurements showed in some instances slightly increased workpiece surface hardness of around 50-60HK(0.025) for the BuRTi alloy and 200HK(0.025) for the gamma-TiA1 material over respective bulk hardness values of 375HK(0.025) and 400HK(0.025).(0 (C) 2006 Elsevier Ltd. All rights reserved.