Mechanical properties of Cr2AlC ceramics

Dense and predominantly single-phase samples of Cr(2)AlC, together with a trace amount of Cr(7)C(3), were fabricated by hot pressing of a mixture of chromium, aluminum, and graphite powders at 1400 degrees C for 1 h. The hardness, Young's modulus, flexural strength, and compressive strength of Cr(2)AlC samples were 5.2, 288 GPa, 483 +/- 29, and 1159 +/- 23 MPa, respectively, which are comparable with those of Ti(3)AlC(2) and Nb(2)AlC. The material exhibits good damage tolerance. For indentation loads up to 50 N, the post-indentation flexural strengths decrease by approximately 10% and by 31% for a load of 100 N. The flexural strengths of Cr(2)AlC samples quenched from 300 degrees C to room temperature decrease from 483 to 455 MPa, while the retained strengths decrease quickly to 199 MPa when the quench temperature increases to 500 degrees C. A further increase in quench temperature to 700 degrees, 900 degrees, and 1100 degrees C results in a small reduction of strength.