Influence of Preliminary Plastic Deformation on the Low-Cycle Fatigue of a Titanium Alloy under Conditions of Deep Cooling

We consider the results of testing of PT3V titanium alloy (4.5% Al, 2.1% V, balance Ti) for low-cycle fatigue at temperatures of 293, 77, and 4.2 K, taking into account the influence of the degree (0.05, 1.0, and 3.0%) of plastic prestraining of the material (performed at the same temperatures) on durability. To simplify the procedure of testing and data processing and decrease the costs of testing, we apply the methods of mathematical design of experiments and factor analysis. It is shown that the maximum decrease in the durability of the tested alloy is attained for a degree of prestraining of 3% at a testing temperature of 4.2 K realized in liquid helium.