The　solubilities　of　Er　and　Yb　in　Al　at　high　temperature　were　evaluated　from　the　electrical　resistivity　measurement,　from　which　the　DS　and　Delta　H　were　estimated　to　be　3.0　+/-　0.1k　and　-0.86　+/-　0.01　eV　for　Al-Er　alloys,　3.7　+/-　1.0k　and　-0.93　+/-　0.07　eV　for　Al-Yb　alloys,　respectively.　The　solubility　curves　of　Er　and　Yb　therefore　could　be　obtained.　According　to　the　solubility　curves　of　Er　and　Yb,　on　the　one　hand,　the　largest　volume　fractions　of　Al3Er,　Al3Yb　at　room　temperature　were　calculated　to　be　0.18%,　0.10%,　respectively,　which　were　obviously　less　than　that　of　Al3Sc,　i.e.,　0.92%.　On　the　other　hand,　the　free　energy　per　unit　volume　for　the　nucleation　of　trialuminides　was　evaluated　with　the　consideration　of　Gibbs-Thomson　effect.　According　to　the　obtained　chemical　driving　force,　the　corresponding　critical　radius,　critical　nucleation　energy　and　the　steady　state　nucleation　rate　could　be　further　calculated.　The　results　indicated　that　in　the　binary　alloys　with　the　same　concentration　at　the　same　temperature,　comparing　with　Al3Sc,　Al3Yb　and　Al3Er　showed　smaller　critical　radius　and　larger　steady　state　nucleation　rate,　which　implied　that　in　Al-Yb　and　Al-Er　alloys,　higher　number　density　of　fine　precipitates　would　be　possibly　existed.　(C)　2014　Published　by　Elsevier　B.V.