Evaluation of thermally-assisted fracture of particles using microscale fracture measurements

Abstract

Thermal pretreatment can significantly improve industrial comminution operations by reducing energy requirements. The effect of pretreatment using conventional and dielectric heating followed by quenching on the microstructure and on the fracture characteristics of selected single-phase and multiphase materials has been investigated using single-particle fracture experiments, crack density measurements and indentation fracture. It was shown that measurements of the crack density from polished sections correlated very well to a parameter related to material integrity, called damage, which makes the latter a very good tool to assess pretreatment. It has been observed that very significant reductions in both fracture energy and material integrity were achieved by heating followed by water quenching.