This is an example of a hypoeutectic alloy. On slow cooling the liquid first solidified at approximately 940°C as copper rich dendrites. The composition of the remaining liquid became increasingly rich in phosphorus until it solidified as a eutectic (8.38 wt% P) at the eutectic temperature of 714°C. Note that the dendrites are cored - the different contrast after etching indicated that the composition varies with position in the dendrites. This is caused by non-equilibrium solidification. The cooling rate was too rapid for equilibrium to be maintained between the solid and the liquid phases. This alloy has no practical applications. Phosphor bronzes usually contain 5 wt% Sn for solid solution strengthening with 0.2 wt% P for interstitial solution strengthening. They have high strength and corrosion resistance and are usually used for springs.
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