Mechanical Properties of CoAl Materials with the Combined Additions of ZrO ₂ (3Y) and Al ₂ O ₃

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Intermetallic CoAl powder has been prepared via self‐propagating high‐temperature synthesis (SHS). Dense CoAl materials (99.6% of theoretical) with the combined additions of ZrO 2 (3Y) and Al 2 O 3 have been fabricated via spark plasma sintering (SPS) for 10 min at 1300°C and 30 MPa. The microstructures are such that tetragonal ZrO 2 (0.3 μm) and Al 2 O 3 (0.5 μm) particles are located at the grain boundaries of the CoAl (8.5 μm) matrix. Improved mechanical properties are obtained; especially the fracture toughness and the bending strength of the materials with ZrO 2 (3Y)/Al 2 O 3 = 16/4 mol% are 3.87 MPa·m 1/2 and 1080 MPa, respectively, and high strength (>600 MPa) can be retained up to 1000°C.