Solidification of undercooled Ag–Cu eutectic alloy with the Sb addition

Effect of Sb Addition on the Solidification of Deeply Undercooled Ag-28.1 wt. % Cu Eutectic Alloy

“…Taking 76 K as a critical undercooling, the alloys solidify in a form of cellular eutectics, cellular dendritic eutectics and the undeveloped dendritic eutectics at lower undercooling but dendritic eutectics at larger undercooling. The solidification of the alloys undercooled no more than 76 K has been reported previously [16]. Here, we pay attention to the solidification of the alloys undercooled above 76 K. For Ag-28.1Cu eutectic alloy, developed dendrites on the sample surface are observed under the SEM (Figure 4a).…”

“…Most of Sb can be dissolved in the Ag-rich (α) and Cu-rich (β) phases during solidification to form substitutional solid solutions [16]. Figure 3a,b show that only α-Ag and β-Cu face-centered cubic phases exist in the solidification structures of (Ag-28.1Cu)-0.5Sb and (Ag-28.1Cu)-1Sb alloys, no matter how large the undercooling is.…”

Determination of the Origin of Anomalous Eutectic Structures from <i>In Situ</i> Observation of Recalescence Behaviour

“…In particular, as the liquid is progressively undercooled a number of systems, including Ni-Sn [1,2], Ni-Si [3,4], Co-Sn [4] and Ag-Cu [5,6], have been reported to display a transition from a regular lamellar to an anomalous eutectic structure. In most cases this is a progressive transition, with increasing volume fractions of the anomalous eutectic being formed as the undercooling is increased.…”

“…Suggestions for the mechanism have included the decomposition of a dendritic supersaturated single-phase solid-solution [1], decoupled growth of the lamellar eutectic [4,7], fragmentation or remelting of primary lamellar eutectics [3,6] and remelting of eutectic dendrites [8]. The issue has been clarified somewhat by the recent work of Yang et al [2] who observed that within the same alloy the anomalous eutectic may have a dual origin.…”

“…This was further investigated in a study [6] looking at the effect of the inclusion of small amounts of Sb in Ag-Cu alloys. It was found that the addition of a third component caused a transition from cellular to dendritic structure at low undercoolings.…”