Effects of elemental Nb addition on the microstructures and mechanical properties of Ti/Al2O3 composites by pressureless sintering

Junyan WU; Xueqian ZHANG; Zhihao WANG; Hao WU; Zhi WANG; Qinggang LI; Qian LIU; Fangfang QI

doi:10.2109/jcersj2.18187

Regular Issue: Full papers

Effects of elemental Nb addition on the microstructures and mechanical properties of Ti/Al₂O₃ composites by pressureless sintering

Junyan WU, Xueqian ZHANG, Zhihao WANG, Hao WU, Zhi WANG, Qinggang LI, Qian LIU, Fangfang QI

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Keywords: Ti/Al₂O₃ composites, Nb addition, Pressureless sintering

JOURNAL FREE ACCESS

2019 Volume 127 Issue 6 Pages 421-427

DOI https://doi.org/10.2109/jcersj2.18187

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Abstract

Nb and Nb₂O₅ were used, respectively, as sintering additives for pressureless sintering of Ti/Al₂O₃ composites, and the effect of elemental Nb on the microstructures and mechanical properties of the composites were investigated. The X-ray diffraction results indicated that the addition of both Nb and Nb₂O₅ resulted in the solution of Nb in Ti. Compared to metal Nb, the addition of Nb₂O₅ made the composites easier to sinter, and the density of the Ti/Al₂O₃ composite rose with increases in the Nb₂O₅ addition. When metal Nb was added, the changes in flexural strength and micro-hardness were basically consistent with the variations in density. The strength of the Ti/Al₂O₃ composites was found to increase at first and then to decrease, however when Nb₂O₅ was added. The phase formation and strengthening mechanisms are illustrated. The best performance occurred when 5 vol.% Nb₂O₅ was added, with a relative density, micro-hardness and flexural strength of 89.3%, 5.6 GPa and 115.78 MPa, respectively.

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