Shell-like nanolayered Nb4AlC3 ceramic with high strength and toughness

Textured nanolayered Nb4AlC3 ceramic possesses a shell-like microstructure configuration from the nanoscale to the milliscale. About 15 vol.% Nb–Al–O oxide particles formed in situ were homogeneously distributed in the Nb4AlC3 matrix. It has a high flexural strength of 1219.2 MPa perpendicular to the c-axis direction and a high fracture toughness of 17.9 MPa m1/2 parallel to the c-axis direction. Also, this ceramic showed excellent machinability and could be easily machined by a high-speed steel cutter.