Rare earth microalloying in as-cast and homogenized alloys Cu–6 wt.% Ag and Cu–24 wt.% Ag

Abstract

Alloys Cu–6 wt.% Ag and Cu–24 wt.% Ag were prepared by casting and homogenization treatment. The effect of rare earth additions on the as-cast and homogenized microstructure was investigated by adding 0.1 wt.% rare earth elements into both the alloys. Adding rare earth elements results in higher eutectic proportion in both alloys, finer primary α grains in the Cu–6 wt.% Ag and more disperse α plates in the eutectic structure of the Cu–24 wt.% Ag. Homogenization treatment produces secondary Ag-rich particles in the α matrix in both alloys and the secondary precipitates in the alloy with high Ag content have higher proportion and more distinct morphology than in the alloy with low Ag content. Adding rare earth elements can result in finer and more uniform secondary precipitates in both the homogenized alloys. The Ag concentration in the eutectic structure in all alloys significantly increases after homogenization treatment and the homogenized alloys containing rare earth elements have higher Ag concentration in the eutectic structure than those non-containing rare earth elements.