Effect of hot-forging on mechanical properties of silicon carbide sintered with Al2O3-Y2O3-MgO

The mechanical properties of hot-pressed and hot-forged SiC were investigated. The hot-forging of the hotpressed SiC was carried out at 1700 A degrees C for 66 h under an applied pressure of 25 MPa in an argon atmosphere. The microstructures on the surfaces parallel and perpendicular to the pressing direction of the hot-pressed and hot-forged SiC were similar, and no texture development was observed because of the lack of massive beta -> I +/- transformation of SiC. An increase in hardness of about 13 % and fracture toughness of about 33 % was achieved in the hot-forged specimens compared to the hot-pressed specimens.