A method of forming a polycrystalline diamond compact comprises providing metallized diamond particles including diamond particles including nanograins of a sweep catalyst secured thereto, the sweep catalyst comprising at least one of tungsten and tungsten carbide and constituting between about 0.01 weight percent and about 1.0 weight percent of the metallized diamond particles and placing the metallized diamond particles and a metal solvent catalyst in a container. The metallized diamond particles are subjected to a high-temperature, high-pressure process in the presence of the metal solvent catalyst to form a polycrystalline diamond material having inter-bonded diamond grains and nanograins of tungsten carbide, the nanograins of tungsten carbide covering less than about twenty percent of a surface area of the inter-bonded diamond grains. Polycrystalline diamond compacts and earth-boring tools including the polycrystalline diamond compacts are also disclosed.