Mechanical characteristics and high temperature stability of oxidized Ti3AlC2 nanolaminat

Abstract

The oxide film formed on the surface of the highly dense (ρ=4.27 g/cm³, porosity 1 %) material based on nanolaminated MAX phase Ti₃AlC₂ (89 % Ti₃AlC₂, 6 % TiC, 5 % Al₂O₃) manufactured by hot pressing (at 30 MPa) made the material highly resistant in air at high temperatures: after 1000 hours of exposition at 600 °C it demonstrated a higher resistance to oxidation than chromium ferrite steels (Crofer GPU and JDA types). Due to the surface oxidation self-healing of defects took place. Besides, the Ti₃AlC₂ material demonstrated resistance against high-temperature creep and after being kept in H₂ at 600 °C for 3h its bending strength reduced by 5 % only. At room temperature the Ti₃AlC₂ bulk exhibited microhardness Hμ = 4.6 GPa (at 5 N), hardness HV₅₀ = 630 (at 50 N ) and HRA = 70 (at 600 N), Young modulus was 140 ± 29 GPa, bending strength =500 MPa, compression strength 700 MPa, and fracture toughness K_1C=10.2 MPa·m^0.5.