This research is to investigate tribological properties of thermal diffusion (TD) treated D2 steels against aluminum (Al 6061) counterface material for its potential applications in dry machining/forming of aluminum composite materials. A hard vanadium carbide (VC) layer was formed on the tool steels by the TD process. Original D2, thermal treatment hardened D2 and TiN coating on hardened D2 were used as references. Pin-on-disc tribo-tests were performed on those samples against Al pins under a dry sliding condition. Wyko profilemetry analysis showed that Al pin material transferred to the D2, hardened D2 and TiN coating surface and caused adhesive wear, which may negatively influence product quality in machining/forming applications. The TD-VC coating on D2 steel has a good adhesive wear resistance and anti-sticking of aluminum performance, which is a promising material used for dry machining/forming of aluminum.