Microstructure and mechanical properties of TiB₂-based composites with high volume fraction of Fe-Ni additives prepared by vacuum pressureless sintering

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• 作者：Ning Wu ; Fengdan Xue ; Qiumin Yang ; Hailin Yang ; ^{y-hailin@csu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Jianming Ruan ; ^{jianming@csu.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Titanium diboride ; Fe-Ni additives ; Vacuum pressureless sintering ; Mechanical properties ; Microstructure
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：1394-1401
• 全文大小：4044 K

文摘

TiB₂-based composites with high volume fraction of Fe-Ni as additive were fabricated by vacuum pressureless sintering. The effect of Fe-Ni addition (Fe:Ni=6:4) at different volume fractions from 20 to 35 vol% on the microstructure evolution and fracture behaviour of the TiB₂-(Fe-Ni) composites was investigated. It was found that the TiB₂-(Fe-Ni) composites consisted of only TiB₂ and γ(Fe, Ni) phases without any brittle phases. The relative density, flexural strength and fracture toughness of the composites increased as the Fe-Ni content increased. The results indicated that the TiB₂–35 vol% (Fe-Ni) composites exhibited the optimum combination of physical and mechanical properties, i.e., the relative density of 98.32%, the Vickers hardness of 8.56 GPa, the flexural strength of 1050.92 MPa and the fracture toughness of 17.75 MPa m^1/2. The high fracture toughness of the TiB₂–35 vol% (Fe-Ni) composite was due to an intensive coupled mechanism of the near-full density, dimple fracture of Fe-Ni phase, crack deflection, crack bridging, grain's pull-out and transgranular fracture of the TiB₂ particles.