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

Abstract

The mechanical properties of hot-pressed and hot-forged SiC were investigated. The hot -forging of the hotpressed SiC was carried out at 1700°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 β→α 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.

Joining of silicon carbide ceramics using a silicon carbide tape

“…Although some residual pores were observed in the interlayers, fairly well densified interlayers were obtained. The Al 2 O 3 –Y 2 O 3 –MgO additives react with SiO 2 , a native oxide film on SiC particles, forming an Al–Y–Mg–Si–O melt during heating in argon atmosphere; with the increase in the temperature, an Al–Y–Mg–Si–O–C melt is formed owing to the dissolution of SiC during the sintering in argon atmosphere . The liquid phases were responsible for the densification of the interlayer through liquid‐phase sintering and bonding between the interlayer and base SiC material.…”

Preparation and anisotropic properties of textured structural ceramics: A review

“…The c-axis of α-SiC can be oriented parallel to the magnetic field direction, and the anisometric shape of SiC also makes it can be easily textured by hot working and TGG [275][276][277]. The preferred orientation growth and texture formation in SiC ceramics are usually resulted from the phase transformation from β-SiC with the cubic crystal lattice to α-SiC with the hexagonal crystal lattice, and the phase transformation usually happens during HF of the sintered specimens at high temperature, which can greatly improve their mechanical properties [160,278]. Lee et al [279] prepared textured SiC-YAG composites by HP and subsequent HF.…”