Polycrystalline compacts including nanoparticulate inclusions, cutting elements and earth-boring tools including such compacts, and methods of forming same

A polycrystalline compact, comprising:

• a plurality of grains of hard material having a first thermal conductivity at 23° C.;
• and
• a plurality of nanoparticles comprising alumina and having a second thermal conductivity at 23° C. disposed in interstitial spaces between the plurality of grains of hard material;
• wherein the second thermal conductivity is about 0.2 Wm−1K−1 or less.

An earth-boring tool, comprising:

• a polycrystalline compact having:
• a plurality of grains of hard material having a first thermal conductivity at 23° C.;
• and
• a plurality of nanoparticles comprising alumina and having a second thermal conductivity at 23° C. disposed in interstitial spaces between the plurality of grains of hard material;
• wherein the second thermal conductivity is less than about 0.2 times the first thermal conductivity.

A method of forming a polycrystalline compact, comprising:

• combining a plurality of interbonded polycrystalline hard particles having a first thermal conductivity at 23° C. and a plurality of nanoparticles comprising alumina disposed in interstitial spaces between the plurality of hard particles and having a second thermal conductivity at 23° C. to form a mixture;
• and
• sintering the mixture to form a polycrystalline hard material comprising a plurality of interbonded grains of hard material;
• wherein the second thermal conductivity is less than about 0.2 times the first thermal conductivity.