A method includes providing a metallic first powder having a plurality of first particles with a first mean particle diameter. A second powder added to the first powder has a plurality of second particles with a second mean particle diameter less than the first mean particle diameter. Energy is applied to at least the second powder so as to selectively heat the second particles. The first powder is combined with the heated second powder to form a modified powder including modified powder particles. Modified powder particles have an interior portion containing an interior composition, and an outer surface portion with an outer composition different from the interior composition.