INFLUENCE OF HYDROGEN ON PLASTIC FLOW OF THE TITANIUM AND ITS ALLOYS

The relevance is established by the widespread titanium application in the modern machine engineering on the one hand, on the other hand – by low manufacturability. In this context, this article is aimed to exposure fundamental laws of the reversing hydrogen alloying for the titanium alloys manufacturability improvement during the plastic yield process. Deformability of titanium alloys, formation of the structure and properties during deformation and the influence of hydrogen on these processes has been extensively studied recently [1-14]. The leading research approach is to determine stress-related characteristics by the compression-test method at the isothermal conditions and then to compare the results for three different alloys: commercial titanium, α - Ti-6Al alloy and α+β – Ti-6Al-4V alloy. Hydrogen alloying is also used as a flexible phase composition management tool for the investigated alloys. In this paper the effect of hydrogen as an alloying element on the yield stress in commercial titanium and Ti-6Al and Ti-6Al-4V alloys is investigated. The connection is made between the strain resistance and phase composition in the wide range of temperatures. It has been found that the hydrogen alloying of commercial titanium in the α-field is accompanied by the yield stress decrease. The role of volume phase ratio in the alloys softening in α+β-field has been shown. The hydrogen hardening parameters in α-field are defined. The paper materials are of a usage value for researchers and technologists, developing innovative technological processes of strained semi-finished titanium products manufacturing.