Although　rare　earth　zirconates　(RE2Zr2O7)　have　garnered　attention　as　viable　candidates　for　thermal　barrier　coatings　(TBCs),　they　suffer　from　low　fracture　toughness　and　accelerated　calcium–magnesium–alumina–silicate　(CMAS)　melt　corrosion　at　high　service　temperatures,　which　impedes　their　practical　application.　In　this　work,　we　developed　a　series　of　REAlO3/RE2Zr2O7　(RE　=　La,　Nd,　Sm,　Eu,　Gd,　and　Dy)　composites　with　a　eutectic　composition　that　not　only　significantly　enhanced　the　fracture　toughness　by　more　than　40%　relative　to　that　of　RE2Zr2O7　but　also　exhibited　improved　resistance　to　CMAS　corrosion.　The　increase　in　toughness　arises　from　multiple　mechanisms,　such　as　ferroelastic　toughening,　fine-grain　strengthening,　and　residual　stress　toughening,　all　of　which　trigger　more　crack　defects　and　energy　consumption.　Additionally,　the　CMAS　penetration　depth　of　the　REAlO3/RE2Zr2O7　composites　is　approximately　36%　lower　than　that　of　RE2Zr2O7.　Al–O　constituents　in　composites　can　capture　CaO,　SiO2,　and　MgO　in　CMAS　melts　and　increase　their　viscosity,　resulting　in　enhanced　CMAS　corrosion　resistance.　The　thermophysical　properties　of　the　REAlO3/RE2Zr2O7　composites　were　also　investigated,　and　their　coefficient　of　thermal　expansion　and　thermal　conductivity　are　comparable　to　those　of　7–8　wt　%Y2O3　partially　stabilized　ZrO2　(YSZ),　indicating　their　potential　as　TBC　materials.　©　The　Author(s)　2024.