Cost‐effective fabrication of α‐SiAlON ceramics with CeO ₂ addition for cutting tool applications

Abstract SiAlON ceramic tools exhibit unique performance superiority in the machining of nickel‐based heat‐resistant superalloys (HRSA). Production cost is a critical obstacle for the wide application of SiAlON inserts. In this work, the cost‐effective preparation of α‐SiAlON ceramics was implemented using aqueous slurry, and the effects of CeO ₂ content on the densification, phase composition, microstructure, mechanical properties, and toughening mechanism of the materials were investigated. The addition of CeO ₂ enhanced the anisotropic growth of α‐SiAlON grains, which enabled the ceramics to obtain higher flexural strength and fracture toughness. Although a decrease in Vickers hardness would occur when CeO ₂ content was 3 or 5 wt.%, ascribed to the amount increase of the intergranular phase in the samples. The α‐SiAlON ceramics doped with 1‐wt.% CeO ₂ achieved the extremely high density and mechanical properties with the relative density, flexural strength, Vickers hardness, and fracture toughness of 99.6% ± .1%, 931 ± 62 MPa, 19.7 ± .2 GPa, and 7.2 ± .2 MPa m ^1/2 , respectively, which could be a candidate cutting tool material for use in the efficient machining of nickel‐based HRSA.