Papers by Author: Pavlo E. Markovsky

Abstract: The trade-off between strength and toughness remains a major challenge in structural materials engineering, especially for titanium-based materials. This study explores the potential of titanium-based laminates for lightweight armor, aimed at improving anti-ballistic properties through the use of layered structures. Titanium alloy Ti-6Al-4V (Ti64) was combined with metal matrix composites (MMCs) reinforced with TiC or TiB particles (up to 40 vol%) using two powder metallurgy (PM) techniques. The first approach used press-and-sinter blended elemental powder metallurgy (BEPM) to create the laminates in a single step, while the second involved post-processing via hot isostatic pressing (HIP) to enhance material properties. Both fabrication methods produced laminates that significantly outperformed commercial alternatives in ballistic testing against 7.62 mm armor-piercing bullets. The use of HIP post-BEPM enhances material properties by reducing porosity and increasing hardness, highlighting the complementary nature of these technologies in producing efficient and cost-effective armor materials.

Abstract: Titanium-based materials are attractive candidates to make low-weight armor parts. However, a broad use of titanium is limited by its high cost, especially when traditional cast and wrought technology is in place. This issue requires more economical production and improved protective properties of titanium-based materials. Powder metallurgy is a valid alternative to make products less expensive, especially when low-cost hydrogenated titanium is used instead of high-quality titanium powder. For effective protection, titanium-based armor should exhibit a substantially improved combination of hardness, strength and ductility, which can be achieved by using laminate (layered) structures. In this study, laminates based on Ti-6Al-4V (wt.%) alloy and its composites reinforced with light and hard particles of TiC and TiB were made using blended elemental powder metallurgy of hydrogenated titanium. Simplest press-and-sinter option as well as additional hot isostatic pressing were tested to achieve high set of characteristics of individual layers and laminates as a whole. It has been shown that the used reinforcement presents an exceptional opportunity for hardening of Ti-based composites without compromising their low specific weight and capable of hardness increase by more than 40% compared to the base alloy. Fabricated structures were ballistic tested and compared with open data on commercial armor made of titanium.

Abstract: High specific strength of Ti-based alloys and composites makes them highly requested materials in various structural applications, especially when lightweight is desired in high-strength constructions. When these alloys are used in layered structures, far advanced set of characteristics that combine different mechanical properties often non-compatible in a single layer uniform structure can be attained; for instance, high hardness or moduli systems are usually lacking of sufficient toughness. Mechanical properties of individual layer in multilayered materials can be controlled by changing chemical composition and microstructure within each layer specifically. In present study layered materials were formed by combination of the layer of Ti-6Al-4V alloy and metal matrix composites on its base reinforced with fine TiB and TiC particles. Structures were fabricated using blended elemental powder metallurgy (BEPM). The effect of different post-sintering thermo-mechanical treatments on structure of layered BEPM materials was studied. Processing parameters were assessed in terms of their influence on materials’ porosity, grain size and structure, distribution of reinforcement particles and layers integration. The effect of above mentioned structural characteristics on hardness of layered materials was evaluated.

Abstract: Taking three titanium commercial alloys: commercial purity titanium (c.p.Ti, single-phase α), Ti64 (Ti-6(wt.%)Al-4V, two-phase α+β) and TIMETAL-LCB (Ti-1.5Al-4.5Fe-6.8Mo, both two-phase α+β and single-phase β) as program materials, the influence of phase composition, microstructure and deformation rate (V_D, varied from 10^-4 to 10¹ s^-1), and deformation mode (compression and 3-point flexure) on the mechanical behavior was studied and compared with data earlier obtained during tensile tests. The size of the matrix phase (alpha- or beta-grains) size and morphology of α+β intragranular mixture were varied using different treatments. Deformation Energy (U_D) was used for analysis of the mechanical behavior of the materials tested. It was found that the U_D dependencies on deformation rate are different for different methods of loading and are determined by a combination of the phase composition, dispersion, and morphology of the phase constituents. More ductile and less dependent on V_D behavior showed c.p.Ti and Ti64 with globular microstructure on all three testing modes, while other materials had some negative features depending on the certain test conditions. Details of mechanical behavior, peculiarities of pores and cracks nucleation causing in final fracture are discussed basing on the results of detailed microstructure study of tested specimens.

Abstract: Local Rapid Heat Treatment (LRHT) based on induction-heating methods can be used to form unique location-specific microstructures and properties in commercial titanium alloys while maintaining the bulk of the material in an initial, non-heat-treated condition. The present work is focused on practical aspects of LRHT application for microstructure/ mechanical properties improvement of some parts made of commercial titanium alloys. It is shown, that LRHT application could improve mechanical properties of such complicated part like turbine engine compressor blades, and two made of Ti-6Al-4V and VT22 titanium alloys goods after repair with Electron Beam Physical Vapor Deposition as well as with Build-up Welding.