Rapid Densification and Deformation of Li-Doped Sialon Ceramics
Two lithium-doped sialon ceramics were densified and superplastically deformed by spark plasma sintering (SPS). Rapid densification with linear shrinkage rates of approximately 5 × 10−3 s−1 were observed for samples heated at a rate of 100°C/min up to ∼1400°C under a uniaxial pressure of 40 MPa. Isothermal deformation by SPS-preprepared, fully densified ceramics performed at T≥ 1450°C yielded strain rates in the order of 10−2 s−2. It is suggested that a high heating rate promotes material transport via formation of a nonequilibrated oxygen-rich liquid of low viscosity. This finding most likely holds true for other liquid-phase sintered ceramics as well and has implications for cost-effective manufacturing of ceramic components.
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