The influence of the deformation and heat treatment on the structure and heat-resistant properties of Ti–Al–Zr–Si alloys

Keywords

heat-resistant titanium alloys, strength, heat-resistance, structure, silicides.

Cite as

Shevchenko O. M., Kulak L. D., Kuzmenko M. M., Koval O. Yu., Kotko A. V., Kravchenko I. F., and Firstov S. O. The influence of the deformation and heat treatment on the structure and heat-resistant properties of Ti–Al–Zr–Si alloys. Physicochemical Mechanics of Materials. 2023. 59(1), 44-52.

https://doi.org/10.15407/pcmm2023.01.044

Abstract

The heat-resistant Ti–Al–Zr–Si alloys (basic Ti–(6–7)Al–(2–3) Zr–(1–1.5)Si and addi­tionally alloyed Ti–(6–7)Al–(3–5)Zr–(1–1.5)Si–(2–4)Sn), obtained by electron beam smel­ting were studied. Deformation was carried out in the b- or upper part of the (a+b)-area by means of forging and rolling into a strip. The influence of deformation and heat treatment modes on the structure and heat-resistant properties of the obtained alloys was investigated. The rolling, which was carried out at the upper part of the a+b area, and the fine-grained uniform structure with a grain size of 10-20 mm in the base alloy was obtained. Internal stresses and defective substructure of the deformed alloy intensify the decomposition of the solid solution and promote the formation of evenly distributed dispersed silicides, which allows obtaining high strength and heat resistance characteristics. Tensile tests at 20; 650 and 700°C of the Ti–(6–7)Al–(2–3)Zr–(1–1.5)Si alloy samples after deformation and annealing also showed a fairly high level of the tensile strength and yield strength, the relative elongation meets the requirements for heat-resistant alloys. As a result of holding 20 h at the operating temperature of 700°C, the structure becomes more equilibrium, due to which the strength level of the deformed alloy decreases, and the relative elongation increases. Additional alloying of the base alloy with zirconium and tin slightly increases plasticity and decrease heat-resistant properties.

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