| Abstrakt: |
A TiB2-based cermet tool material with excellent mechanical performance was rapidly prepared by microwave hybrid sintering. Microwave hybrid sintering is based on pure microwave sintering with the addition of high microwave absorbing materials (e.g., SiC coating and SiC powder) to assist in the heating of the sample, which has the characteristics of hybrid heating. The effects of two different microwave hybrid sintering methods and nano-HfC content on mechanical properties and microstructure of cermets were investigated. The experimental results indicated that different sintering methods changed the distribution of microwave electric field in the furnace, which affected the sample heating mechanism. SiC-buried powder hybrid sintering was more efficient than SiC coating hybrid sintering, so the sintered material had higher densities and mechanical properties. The fracture toughness and flexural strength of cermets containing 20 wt.% HfC were 36.7% and 45.4%, respectively, higher than those without HfC, and the fracture toughness reached 10.68 MPa·m1/2. With the increase of nano-HfC content, the TiB2 grains changed from coarse irregular shape to fine rectangular shape, and the average grain size can be reduced by 2.6 times. The toughening and strengthening mechanisms of the nano-HfC added phase were mainly fine-grain strengthening, particle dispersion strengthening, solid solution strengthening, crack deflection, and pinning effect. [ABSTRACT FROM AUTHOR] |
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