Titanium alloys are widely used in various aerospace, marine, chemical industries, medical, and military applications because these alloys have high specific strength, high Young’s modulus, and excellent corrosion resistance. In particular, when a lot of organic composite materials such as carbon fibre-reinforced plastics (CFRP) are applied to aircraft components to decrease the weight reduction, titanium materials are also used because their thermal coefficient of expansion is similar to that of CFRP and titanium is not subject to damage by galvanic corrosion in contact with CFRP materials.
Oxygen can dissolve in titanium to form an interstitial solid solution in a large amount (34 at.% in alpha titanium), it shows a strong hardness and mechanical strengthening on titanium matrix. Therefore, instead of expensive rare metals such as vanadium (V), oxygen (O) is usually used as a attractive interstitial solid solution strengthening element.
Results of experimental investigations of the influence of a oxygen-containing gaseous medium on the kinetics of interaction of titanium alloys of different structural classes (α-, pseudo-α, (α+β)) are presented in this paper. It is established that under the same conditions of saturation (T, τ, P) the hardened layers of various parameters (H, l) are formed on the titanium alloys. The monophase α-titanium alloys VT1-0, VT5 and pseudo-α-alloy ОТ4-1 are the most sensitive to the conditions of gas-saturation: gain of surface hardness and its gradient in the hardened layer increases sufficiently. With increasing of β-phase (OT4®VT16) changing of the parameters of CTT has less influence on the hardness of surface layer, but the depth of the hardened zone is being increased with increasing of the temperature and exposure time.
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