Phase equilibrium in Ag-Pd-Cu dental alloys.
A dental alloy consisting of Ag-Pd-Cu-Au has been annealed at various temperatures and subsequently quenched to produce a solid solution before a hardening heat treatment. The phases present were studied by means of X-ray diffraction measurements. As in conventional Au-Ag-Cu alloys, an equilibrium of two FCC (face-centered cubic) phases existed up to the solid solution annealing temperature, which is considerably higher in the present alloy (900 degrees C). However, even a rapid quench from 900 degrees C caused a small amount of decomposition of the matrix. The X-ray diffractogram indicated that this new phase is CuPd with a CsCl(B2) superstructure. The greatest hardness after age-hardening at 350 degrees C was achieved with a proper prerequisite solid-solution annealing.
D003300:Copper / Q000032:analysis; D003461:Crystallography; D006047:Gold Alloys / Q000032:analysis; D006244:Hardness; D006358:Hot Temperature; D008669:Metallurgy; D010165:Palladium / Q000032:analysis; D014961:X-Ray Diffraction
D006047:Gold Alloys; D010165:Palladium; D003300:Copper