Machining accuracy in pulsed wire electrochemical machining of gamma-TiAl alloy

摘要

TiAl alloys are identified as promising candidates to replace the heavier Ti- and Ni-based superalloy components in aircraft engines at moderately high temperature, owing to their unique advantages. However, it is still a challenge for modern manufacturing to machine TiAl alloys into engineering components. This paper presents the feasibility of wire electrochemical machining (WECM) of gamma-TiAl alloy (Ti-42Al-6V-1Cr). In order to investigate the machining accuracy, variations in the side gap with some of the predominant electrochemical parameters, namely electrolyte concentration, applied voltage, pulse period, pulse duty cycle, and feed rate, were evaluated. The results showed that the optimum combination of machining parameters were electrolyte concentration of 1.0 % NaCl and 1.0 % NaNO3, applied voltage of 17 V, pulse period of 10 mu s, pulse duty cycle of 20 %, and feed rate of 3.0 mu m/s. Finally, various features with a side gap of 109 mu m and an aspect ratio of 31 were machined into gamma-TiAl alloy workpieces measuring 10 mm in thickness. It revealed that pulsed electrochemical machining technology had a promising application in machining of gamma-TiAl alloy with complex-contour features.