Effect of Rare Earth Er on the Microstructure and Mechanical Properties of High Temperature Titanium Alloys

Abstract:

The microstructures and mechanical properties of the high temperature titanium alloys containing Er, i.e. Ti-6Al-2.5Sn-4Zr-0.3Mo-1Nb-0.35Si-xEr (x=0, 0.1, 0.3wt%), were investigated. Both the grain size and lamellar structure inside grains were significantly refined with the addition of Er in as-cast alloys. Lamellar and duplex microstructures were obtained after forging and heat treatment. Silicide precipitates were generated in the boundary of lamellar α phase after aging treatment. Meanwhile, a few α₂ phase were precipitated in the alloys after aging treatment. After 600°C /100h thermal exposure, the α₂ phases with a mean size of 7nm and spacing of 10 nm were precipitated homogeneously in α lamellar. The creep properties were significantly improved by the addition of rare earth Er due to the formation of the second phase containing Er, silicide and α₂ phase.

• Periodical: Materials Science Forum (Volume 898)
• Pages: 586-591
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.898.586
• Online since: June 2017
• Authors: Bo Long Li*, Tong Bo Wang, Peng Han, Zhen Qiang Wang, Zuo-Ren Nie
• Keywords: Mechanical Properties, Microstructure, Rare Earth Er, Titanium Alloy

References

[1] R.R. Boyer. An Overview on The Use Of Titanium in the Aerospace Industry. Materials Science and Engineering, 1996, A213: 103~114.

[2] W. F Cui, C. M Liu, Characteristics of Microstructures And Second-Phase Particles in Y-Bearing Ti-1100 Alloy. Materials Science and Engineering, 2002, A323, 192~197.

DOI: 10.1016/s0921-5093(01)01362-4

[3] X. Wang et al. Substructure of High Temperature Compressed Titanium Alloy IMI834. Materials Science and Engineering: A, 434(2006): 188-193.

DOI: 10.1016/j.msea.2006.06.119

[4] D.F. Neal. Development of TIMETAL834[A], Materials Design Approaches and Experiences[C], 2001: 199-213.

[5] J. Luo, M.Q. Li. Strain Rate Sensitivity and Strain Hardening Exponent During the Isothermal Compression of Ti60 Alloy. Materials Science and Engineering: A, 2012, 538: 156-163.

DOI: 10.1016/j.msea.2012.01.021

[6] W. J Jia, et al., Influence of Thermal Exposure on the Tensile Properties and Microstructures of Ti60 Titanium Alloy. Materials Science and Engineering: A, 2011, 530: 511-518.

DOI: 10.1016/j.msea.2011.10.011

[7] G. Biallas, et al. Influence of Environment on Fatigue Mechanisms in High Temperature Titanium Alloy IMI834, International Journal of Fatigue, 2005(27): 1485-1493.

DOI: 10.1016/j.ijfatigue.2005.06.009