Thermal Stabilities of Ti-600 Alloy Pancake
Thermal stabilities at ambient temperature were studied on Ti-600 alloy before and after being exposed at 600 °C for 100 h. Fractography morphologies were investigated, and fracture mechanism analyzed. The results indicated that the strength of the alloy sample after thermal exposure decreased 1% or so, the elongation decreased about 49%, indicating that the plasticity decreased abruptly during the exposure process. For the as-solutioned plus as-aged samples, the cracks originate from the center of the fracture, dimple typed fracture can be found in the fractographies. After thermal exposure, only cleavage facets can be observed in the fractographies, the fractures propagate along the interfaces of lamellar α phases. The fractography of the tensile specimen prior to and after thermal exposure presented the feature of intergranular fracture, transgranular plus intergranular rupture, respectively. These results are caused by the precipitation and the existence of the brittle oxidizing layers. The cracks formed in the oxidizing layers first and then propagated into the matrix during the tensile tests. Oxygen filtration in the surface layer was one of the important reasons for the decrease of plasticity. The major deformation mechanism for Ti-600 alloy without and with thermal exposure is dislocation slips pass-through α bundles, α/β phase boundary slips during the tensile deformation process at ambient temperature, respectively.
KeywordsHigh temperature ti alloy Ti-600 Thermal stability Tensile elongation Oxygen filtration
The authors wish to thank financial support from the Major Scientific & Technical Innovation Team Plan Project in Shaanxi Province (No. 2016KTC-27, Seashore Advanced Metals Innovation Team).
- 1.W.J. Jia, W.D. Zeng, H.Q. Yu, Y.G. Zhou, Effect of thermal exposure on properties and fracture behaviors of Ti60 alloy, The Chinese J. Nonferr. Metals. 19 (2009) 1032–1037.Google Scholar
- 2.L.Y. Zeng, Q. Hong, Y.Q. Zhao, Y.L. Qi, Influence of element Si on thermal stability for Ti-600 alloy, The Chinese J. Nonferr. Metals. 23 (2013) s1–s4.Google Scholar
- 3.A.K. Singh, T. Roy, C. Ramachandra, Microstructural stability on aging of an α + β titanium alloy: Ti-6A1-1.6Zr-3.3Mo-0.30Si, Metall. Mater. Trans. A. 27 (1996) 1167–1173.Google Scholar
- 4.L. Christoph, P. Manfred, W. Dirk, W.A. Kaysser, Metall. Mater. Trans. A, 27A. (1996) 1709–1717.Google Scholar
- 5.Z.S. Zhu, X.N. Wang, C.Z. Wu, J.P. Chu, Rare Metals Letters. 26 (2007) 24–28.Google Scholar
- 6.K.V.S. Srinadh, V. Singh. Oxidation behaviour of the near α-titanium alloy IMI 834. Bulletin Mater. Sci., 27 (2004): 347–354.Google Scholar
- 7.M.L. Bauccio, in: R. Boyer, E.W. Collings, H. G. Welsch (Eds.), Materials Properties Handbook: Titanium Alloys, ASM, 1994, pp. 1148–1150.Google Scholar
- 8.F. Borgioli, F.P. Galliano, T. Bacci, E. Galvanetto, Air treatment of pure titanium by furnace and glow-discharge processes. Surface & Coatings Tech. 139 (2001) 103–107.Google Scholar
- 9.W.H. Miller, R.T. Chen, E.A. Starke, Metall. Mater. Trans. A. 18A(1987) 1451–1454.Google Scholar
- 10.X. Feng, The effect of Zr addition on 650°C deformation and fracture mechanisms in Ti-1100 Alloy, Doctor Thesis, Shenyang, Institute of Metal Research, Chinese Academy of Sciences, 2007, 94–99.Google Scholar
- 11.V. Hasija, S. Ghosh, M.J. Mills, Deformation and creep modeling in polycrystalline Ti-6Al alloys. Acta Mater. 51 (2003) 4533–4549.Google Scholar