Al-7Si-0.8Sc-0.6Ce　alloys　were　prepared　with　combined　addition　of　low-cost　Ce　and　high-priced　Sc　through　molten　salt　electrolysis　with　controlled　cooling　process.　The　phases　of　as-casted　alloys　consisted　of　alpha-Al,　eutectic　silicon,　ternary　AlSi2Sc2　and　CeAl2Si2.　Rapid　cooling　transformed　the　huge　hollow　ternary　AlSi2Sc2　blocks　(300-500　mu　m)　into　fine　Al3Sc　particles　(dozens　of　mu　m),　and　simultaneously　refined　the　AlSi2Sc2　with　reducing　its　interlayer　thickness　from　15.26　mu　m　down　to　1.94　mu　m　(the　cooling　rate　from　0.05　K　s-1　up　to　30　K　s-1).　The　eutectic　Si　became　fine　fibrous-like　clusters　and　the　thickness　of　CeAl2Si2　phase　reduced　by　62.6　%　when　the　cooling　rate　reached　30　K　s-1.　Micro-hardness　measurement　and　first　principles-based　calculation　were　applied　for　evaluating　the　individual　mechanical　performance　of　each　phase　in　the　alloy.　The　calculated　Young＇s　modulus　(E)　suggests　that　Al3Sc　(E　=　168　GPa),　AlSi2Sc2　(E　=　178　GPa)　and　CeAl2Si2　(E　=　39.2　GPa)　can　toughen　Al-matrix　(E　=　30.6　GPa).　The　rapid　cooling　(30　K　s-1)　strongly　enhances　all　phase　components　but　diminish　the　huge　hollow　AlSi2Sc2　blocks　(ultrahigh　micro-Vickers　hardness　similar　to　780　HV),　making　a　homogenous　Al-RE　alloy　with　improved　mechanical　property　(68　similar　to　84　HV　balanced　among　phase　components).　The　refining　mechanisms　on　the　improved　mechanical　performance　are　also　discussed.(c)　2023　Elsevier　B.V.　All　rights　reserved.