Influence of indium addition on the AgCu25Zn20Cd20 alloy microstructure

In our investigation of the AgCu25Zn20Cd20 alloy, cadmium was partly or ful ly replaced by indium due to its toxicity. The influence of this substituti on on the fraction, morphology and the distribution of the identified phase s has been examined, and the indium distribution in the single phases was e stablished. Melting intervals of several alloys have been determined and th eir hardness in the cast or in heat-treated state was measured. By means of X-ray diffraction (XRD) phase analysis the intermetallic phase of delta -C uIn has been already established in the alloy with 5 wt.% In. The hardness of the cast alloys was strongly increased and the technological procedures of their manufacture was reduced in the presence of that phase. With higher fraction of indium in the alloy the quantity of the ternary eutectic (alph a (Ag)+alpha (Cu)+beta -AgCd) in the microstructure was decreasing, and the quantity of ternary mixed crystals alpha (Ag) increased up to 60 vol.%, wh ile the quantity of alpha (Cu) remained fixed. By substitution of indium fo r cadmium, the melting point decrease to 586 degreesC and a smaller solidif ication interval in the alloy of AgCu25Cd15Zn20In5 have been observed.