The invention discloses a
toughness-enhanced hard
alloy with a Co binding phase enhanced by Ni3Al. The hard phase of the hard
alloy is WC, and the binding phase is Co and Ni3Al of which the
volume percent is 10-40%. The preparation method of the hard
alloy comprises the following sequential steps of: uniformly mixing 2.07-16.05wt% of Ni
powder and
Al powder with WC
powder according to a composition ratio of Ni25Al; placing the uniformly mixed
powder in a
graphite container at the thickness not more than 50 mm, heating to 1100-1200 DEG C in a non-oxidative
atmosphere at a speed not more than 5DEG C / min, maintaining the temperature for more than 1 hour, and naturally cooling to obtain a mixture of WC and Ni3Al;
grinding, pulverizing and screening to obtain mixed powder with a particle sizebelow 120 mu m; carrying out deoxidation pretreatment in 400+ / -50 DEG C
hydrogen; carrying out pre-wet-
grinding and mixing on 83.26-97.62wt% of mixed powder obtained after deoxidation pretreatment for 6-12 hours, then adding the balance of Co powder, and carrying out
wet grinding for 18-36 hours; carrying out
spray drying and pressure shaping on the wet-ground mixed material; and carrying out low-pressure liquid-phase
sintering on the pressed blank at 1350-1550 DEG C to obtain the WC-Co hard alloy with the binding phase enhanced by Ni3Al. The hard alloy has the advantages that: a gamma' phaseis dispersed and distributed in the binding phase, the binding phase is uniformly distributed, and the alloy has high compactness, high strength, good
wear resistance and excellent high-temperature
oxidation resistance and
corrosion resistance.