Machinability and surface integrity of RR1000 nickel based superalloy

Alloy development for gas turbine components has produced materials able to maintain strength and integrity at operating temperatures up to ∼1050 °C. Next-generation RR1000 nickel-based superalloy reflects this philosophy, albeit at the expense of machinability. Experimental data for drilling showed flank wear when operating at 45 m/min to be <100 μm for a distance cut of 1800 mm (150 holes). Thrust forces measured 1600-1800 N. Re-deposited material on hole surfaces and drag/distortion was evident on cross-sectional micrographs. Roughness of end-milled specimens was <0.8 μm Ra with minimal damage using new tools, however significant burring/increased microhardness (∼150 HK0.05) and white layer formation occurred when employing worn tools.