Effect of Nano HfC on Mechanical Properties and Microstructure of TiB2-based Cermet Tool Materials Sintered by Micro wave Sintering
A TiB2-based cermet tool material with excellent mechanical performance is rapidly prepared by microwave sintering.Effect of nano HfC content on mechanical properties and microstructure of cermets is investigated,and the rela-tionship between microstructure and mechanical properties is analyzed.The strengthening and toughening mechanism of nano HfC on cermet tool materials is revealed.The experiment demonstrates that the addition of nano HfC can significantly improve the fracture toughness and flexural strength of the materials.The fracture toughness and flexural strength of cermets containing 20wt.％HfC are 36.7％and 45.4％higher than those without HfC,and the fracture toughness reaches 10.68MPa·m1/2±0.30MPa m1/2.With the increase of nano HfC content,the TiB2 grains changes from coarse irregular shape to fine rectangular shape,and the average grain size can be reduced to 1/2.6.The main strengthening and toughening mechanisms of TiB2-TiC-HfC cermets are fine grain strengthening,particle dispersion strengthening,solid solution strengthe-ning,crack deflection and pinning effect.
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