Simultaneously enhanced toughness and strain tolerance of SiC-based ceramic composite by in-situ formation of VB₂ particles

详细信息    查看全文

• 作者：Yinsheng Li^a ; ^b ; ^{derek.ys.li@hotmail.com" class="auth_mail" title="E-mail the corresponding author} ; Haibo Wu^a ; ^{wuhaibo@mail.sic.ac.cn" class="auth_mail" title="E-mail the corresponding author} ; Ha-Neul Kim^b ; Xuejian Liu^a ; Zhengren Huang^a ; ^{zhrhuang@mail.sic.ac.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Silicon carbide ; Vanadium diboride ; Particulate composite ; Fracture toughness ; Strain tolerance
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：37
• 期：1
• 页码：399-405
• 全文大小：2737 K

文摘

SiC-30vol%VB₂ ceramic composite was pressureless densified at 2150 °C with excess B₄C and C as sintering aids after in-situ formation of VB₂ in SiC matrix. The sintered bulk gained a considerably high fracture toughness of 7.0 ± 0.4 MPa m^1/2, which was ∼2.4 times as high as that of the monolithic SiC ceramic, owing to the existences of weak heterophase boundaries, thermal residual stresses and microcracks. Meanwhile, since the VB₂ particle has a lower elastic modulus than SiC and significantly suppressed the grain growth of SiC, the composite exhibited a high flexural strength of 458 ± 36 MPa and a relatively low Young’s modulus of 356 ± 6 GPa, resulting in an increase of ∼59.3% in mechanical strain tolerance (1.29 × 10⁻³) compared with that of single-phase SiC ceramic. Besides, the residual stresses and microcracks also induced a lower-than-expected Vickers hardness of 20.8 ± 0.5 GPa in the composite.