Modification of Mechanical Properties of High-Strength Titanium Alloys VT23 and VT23M Due to Impact-Oscillatory Loading

Abstract

A simple technological method is proposed and tested experimentally, which allows for the improvement of mechanical properties in sheet two-phase high-strength titanium alloys VT23 and VT23M on the finished product (rolled metal), due to impact-oscillatory loading. Under impact-oscillatory loading and dynamic non-equilibrium processes (DNP) are realized in titanium alloys, leading to the self-organization of the structure. As a result, the mechanical properties of titanium alloys vary significantly with subsequent loading after the realization of DNP. In this study, the test modes are found, which can be used in the production conditions.

Improving of Mechanical Properties of Titanium Alloy VT23 due to Impact-Oscillatory Loading and the Use of Carbon Nano-Solution

“…A mixture of titanium oxide and titanium carbide or titanium oxycarbide of the TiO 2-x C x type found on the specimen surface generally confirms our working hypothesis concerning the strengthening of the surface layers of the alloy via impact-oscillatory loading and the use of carbon nanosolutions. Indeed, less dense dissipative structures that are created in the volume of the alloy under impact-oscillatory loading are microextruded onto the surface of the specimen, and when the plastic "wave" passes, they are embossed into the alloy, resulting in significant structural changes in the surface layer with the formation of the surface nanostructured layer [27][28][29][30][31].…”

Morphological Characteristics of Dimples of Ductile Fracture of VT23M Titanium Alloy and Identification of Dimples on Fractograms of Different Scale

“…Specimens were loaded with a dynamic impulse and then stretched to fracture statically. The process of mechanical testing is described in detail in [6,7]. Investigation of the fracture surface was performed by scanning electron microscopy using the scanning electron microscope (SEM) REM 106I.…”

“…Titanium alloys are used for the protective clothing of soldiers (plates of body armor), as well as implants, surgical instruments, internal and external prosthetics, including such critical high-tech elements as heart valves. In addition, titanium alloys are used for the manufacture of aircrafts and space vehicles [1,2,3,4,5].…”

“…Fracture patterns of metals in general and high-strength titanium alloys in particular depend on a stage-like nature of damage accumulation during deformation. That is, macro-fracture patterns actually depend on the stage-like nature of transition from the equilibrium to non-equilibrium accumulation of damage, and on the random stage of fracture [6,7]. Deformation causes a plurality of pores concentrated predominantly in the central part of the neck, which coalesce with grain conglomerates leading to the formation of a continuous crack in the plane normal to the direction of loading.…”

Variation of Relief Topography and Hardness of Surface Layers of Materials Due to Impact-Oscillatory Loading

“…The density of these dissipative structures is less than that of the base material. Thus, aluminum alloys are characterized by newly formed dissipative structures in the form of thin-layer structures interconnected at different structural levels [27,28]. Two-phase titanium alloys are characterized by the mechanisms of structure fragmentation [29,30,31,32].…”