Pressureless sintering of titanium carbide doped with boron or boron carbide

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• 作者：Yifeng Gu^a ; ^b ; Ji-Xuan Liu^c ; ^{ljxsic@mail.sic.ac.cn" class="auth_mail" title="E-mail the corresponding author} ; Fangfang Xu^a ; Guo-Jun Zhang^c
• 关键词：Titanium carbide ; Pressureless sintering ; Microstructures ; Mechanical properties
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：37
• 期：2
• 页码：539-547
• 全文大小：3522 K

文摘

Titanium carbide ceramics with different contents of boron or B₄C were pressureless sintered at temperatures from 2100 °C to 2300 °C. Due to the removal of oxide impurities, the onset temperature for TiC grain growth was lowered to 2100 °C and near fully dense (>98%) TiC ceramics were obtained at 2200 °C. TiB₂ platelets and graphite flakes were formed during sintering process. They retard TiC grains from fast growth and reduced the entrapped pores in TiC grains. Therefore, TiC doped with boron or B₄C could achieve higher relative density (>99.5%) than pure TiC (96.67%) at 2300 °C. Mechanical properties including Vickers’ hardness, fracture toughness and flexural strength were investigated. Highest fracture toughness (4.79 ± 0.50 MPa m^1/2) and flexural strength (552.6 ± 23.1 MPa) have been obtained when TiC mixed with B₄C by the mass ratio of 100:5.11. The main toughening mechanisms include crack deflection and pull-out of TiB₂ platelets.