Precipitation behavior of Ag-Pd-In dental alloys

Abstract

Age-hardening characteristics and precipitation behavior of Ag-25%Pd-3%In-1%Zn-0.5%Ir alloy were investigated in detail by means of hardness testing, X-ray diffraction, electron microscopy and resistivity measurement. The solution treating could be accomplished at 980 degrees C and the aging in the temperature range from 950 to 850 degrees C occurred by continuous precipitation. The aging in the temperature range from 850 to 450 degrees C occurred first, forming GP-zones with a hardness increase and then in overaging stage by forming discontinuous precipitation, which consisted of lamellae of solute (Pd, In, Zn) depleted Ag-rich phase and (Pd,Ag)(3)(In,Zn) intermetallic phase. The hardness increased very fast to its peak in 10 min during aging at temperatures between 450 and 550 degrees C. (C) 2000 Kluwer Academic Publishers.