Fabrication and mechanical properties of TiC/TiAl composites

Abstract

TiC/TiAl composites with different TiC content were fabricated by rapid heating technique of spark plasma sintering (SPS). The effect of TiC particles on microstructure and mechanical properties of TiAl matrix was investigated. The results indicate that grain sizes of TiAl matrix decrease and mechanical properties are improved because of the addition of TiC particles. The composites display a 26.8% increase in bending strength when 10wt% TiC is added and 43.8% improvement in fracture toughness when 5wt% TiC is added compared to values of TiC-free materials. Grain-refinement and dispersion-strengthening were the main strengthening mechanism. The improvement of fracture toughness was due to the deflexion of TiC particles to the crack.

Keywords

TiC/TiAl composites / mechanical properties / SPS sintering technique

References

[1] Kim Y W. Ordered Intermetallic Alloys, Part III: Gamma Titanium Aluminides. JOM, 1994, 7: 30-39.

[2] Dimiduk D M. Gamma Titanium Aluminide Alloys—An Assessment within the Competition of Aerospace Structural Materials. Mater. Sci. and Eng., 1999, 263: 281-288.

[3] Deve H E, Evans A G, Shih D S. A High-toughness γ-Titanium Aluminides. Acta Metall Mater, 1992, 40(6): 1259-1259.

[4] Nobuki M, Hashimoto K, Tsujimoto K, . Deformation of TiAl Intermetallic Compound at Elevated Temperatures. J Japan Inst. Met., 1986, 50(9): 840-844.

[5] Wei-min Wang, Zheng-yi Fu, Hao Wang, Run-zhang Yuan. Combustion Synthesis and Densification of NiAl/TiB₂ Composites. Journal of Wuhan University of Technology-Mater. Sci. Ed., 2002, 17(1): 4-4.

[6] Yang J M, Ksi W, Jeng S M. Development of TiC Particle—reinforced MoSi₂ Composites. Scipta Metal, 1989, 23: 1953-1958.

[7] Kumar K S, Whittenberger J D. Discontinuously Reinforced Intermetallic Matrix Composites via XD Synthesis (exothermal dispersion). Mater. Sci. Technol., 1992, 8: 317-317.

[8] Bing-chu Mei, Yan-lin Chen, Li-ping He, . Hardness Measurement of (TiB₂−TiAl)/TiAl Symmetrically Function Gradient Materials. Journal of Wuhan University of Technology-Mater. Sci. Ed., 2002, 17(1): 1-1.

[9] Groza J R. Plasma Activated Sintering of Additive-free AlN Powders to Near-theoretical Density in 5 Minutes. J. Mater. Res., 1992, 7(10): 2643-2645.

[10] Tong X C, Fang H S. Al−TiC Composites in situ—Processed by Ingot Metallurgy and Rapid Solidification Technology I-Microstructural Evolution. Metallurgical and Materials Transactions A, 1998, 29A: 875-875.

[11] xiaonan Mao. Study of Interfacial Stability and Mechanical Properties of Particles Reinforced Ti Matrix Composite, 1999 Shenyang: Northeastern University.