Determination of the enthalpy of fusion and thermal diffusivity for ternary Cu60−xSnxSb40 alloys

• The increasing Sn content reduces the liquidus temperature.
• High Sn content results in lower enthalpy of fusion by polynomial functions.
• The thermal diffusivity drops from the solid toward the semi-solid state.
• Undercoolability of alloys with primary Cu2Sb phase is stronger than others.

The liquidus and solidus temperatures, enthalpy of fusion, and the temperature dependence of thermal diffusivity for ternary Cu60−xSnxSb40 alloys were systematically measured by DSC and laser flash methods. It is found that both the liquidus temperature and the enthalpy of fusion decrease with the rise of Sn content, and their relationships with alloy composition were established by polynomial functions. The thermal diffusivity usually drops from the solid toward the semi-solid state. The undercoolability of those liquid Cu60−xSnxSb40 alloys with primary Cu2Sb solid phase is stronger than the others with primary β(SnSb) intermetallic compound, and the increase of cooling rate facilitates further undercooling. Microstructural observation indicates that both of the primary Cu2Sb and β(SnSb) intermetallic compounds in ternary Cu60−xSnxSb40 alloys grow in faceted mode, and develop into coarse flakes and polygonal blocks.