Ternary eutectic growth during directional solidification of Ag–Cu–Sb alloy

Abstract

The directional solidification process of ternary Ag_42.4Cu_21.6Sb₃₆ eutectic alloy within a wide growth rate range from 2 to 60 μm/s was accomplished at a constant temperature gradient of 50 K/cm. As growth rate increases, the ternary (θ(Cu₂Sb) + ε(Ag₃Sb) + Sb) eutectic morphology evolves from “lamellar (θ + ε) plus fibrous (Sb)” structure into “(θ + Sb) fibres in continuous ε matrix” structure. The θ and (Sb) phase spacings decrease with the increase of growth rate according to power functions with exponent values of 0.55 and 0.56, respectively. It is also found that the microhardness of directionally solidified Ag_42.4Cu_21.6Sb₃₆ alloy samples is enhanced with the increase of growth rate, and the decrease of θ and (Sb) phase spacings.

Keywords:

• phase transformation
• solidification
• microstructure
• microhardness
• ternary eutectic growth

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 51327901], [grant number 51271150], [grant number 51201136]; Aviation Science Foundation of China [grant number 2012ZF53069]; Natural Science Foundation of Shaanxi Province, China [grant number 2013JQ6011]; Fundamental Research Fund of Northwestern Polytechnical University [grant number JCQ01091]; NPU Excellent Personnel Supporting Project of Ao Xiang New Star.