PHASE-TRANSFORMATION IN A DENTAL PD-CU-GA ALLOY

Phase transformation behavior in a dental Pd-Cu-Ga alloy was studied b y means of hardness tests, electrical resistivity measurements, X-ray diffraction and transmission electron microscopy. Annealing at 673 K p roduces two hardness peaks which correspond to the formation of a meta stable phase with ordered fct structure and the precipitation of the e quilibrium phases. alpha(1) (fcc) alpha(2)(fcc) + Pd2Ga (orthorhombic) , respectively. On the other hand. annealing at 873 K exhibits only on e peak due to the precipitation of the equilibrium phases. The differe nce of the phase transformation between both annealings is interpreted in terms of the free energy.