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.

The influence of the composition and structure of a multilayer titanium-based material on its behaviour under impact testing conditions was studied. The material consisted of four consecutive layers of: (i) metal matrix composite (MMC) based on Ti64 alloy (wt. 6.1% Al-4% V) reinforced with 40 vol % dispersed TiC particles, (ii) Ti64 alloy, (iii) porous commercial purity titanium (about 60% pores), and (iv) the bottom layer of Ti64 alloy. MMC and Ti64 alloy layers were deposited on a layer of porous Ti using a coaxial electron beam 3D printing method with a commercial Ti64 wire, and a specially designed cored wire as the feedstock. The overall density of the layered material was less than 3 g/cm3. An impact test conducted with a 7.62 mm calibre armour-piercing cartridge (with a bullet kinetic energy of 3430 J) demonstrated high ballistic resistance when a hard bullet core penetrated the sample to a depth of approximately 20 mm, where it was stopped within the porous titanium layer and subsequently ejected from the sample. The features of the microstructure of this four-layer material in different locations and their role in ballistic resistance are considered and discussed.

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.

Porous materials are extremely efficient in absorbing mechanical energy in different applications. In the present study, porous materials based on the Ti-6(wt.%)Al-4V alloy were manufactured with the use of two different powder metallurgy methods: i) blended elemental powder approach using titanium hydride (TiH2) as well as V-Al master alloy powders and ii) using hydrogenated Ti-6-4 pre-alloyed powder. The powder compacts were sintered with additions of ammonium bicarbonate as a pore-holding removable agent. The emission of hydrogen from hydrogenated powders on vacuum sintering and the resulting shrinkage of powder particles permitted the control of the sintering process and the creation of anticipated porous structures. Mechanical characteristics were evaluated under quasi-static and dynamic compressive loading conditions. Dynamic compression tests were performed using the direct impact Hopkinson pressure bar technique. All investigations aimed at characterizing the mechanical energy-absorbing ability of the obtained porous structures. The anticipated strength, plasticity, and energy- absorbing characteristics of porous Ti-6-4 material were evaluated, and the possibilities of their application were also discussed. Based on the obtained results, it was found that porous Ti-6-4 material produced with a blended elemental powder approach showed more promising energy absorption properties in comparison with pre-alloyed powder.

Metal matrix composites tiles based on Ti-6Al-4V (Ti64) alloy, reinforced with 10, 20, and 40 (vol.%) of either TiC or TiB particles were made using press-and-sinter blended elemental powder metallurgy (BEPM) and then bonded together into 3-layer laminated plates using hot isostatic pressing (HIP). The laminates were ballistically tested and demonstrated superior performance. The microstructure and properties of the laminates were analyzed to determine the effect of the BEPM and HIP processing on the ballistic properties of the layered plates. The effect of porosity in sintered composites on further diffusion bonding of the plates during HIP is analyzed to understand the bonding features at the interfaces between different adjacent layers in the laminate. Exceptional ballistic performance of fabricated structures was explained by a significant reduction in the residual porosity of the BEPM products by their additional processing using HIP, which provides an unprecedented increase in the hardness of the layered composites. It is argued that the combination of the used two technologies, BEPM and HIP is principally complimentary for the materials in question with the abilities to solve the essential problems of each used individually.

The features of formation of the structure, composition and certain mechanical properties of layered materials based on titanium and its alloys during melting by the electron-beam cold-hearth melting technique are considered. The influence of composition in two-layer structures Ti64 (Ti-6Al-4V)/LCB (low-cost beta Ti-1.5Al-6.8Mo- 4.5Fe) and Ti64/Ti5553 (Ti-5Al-5V-5Mo-3Cr), as well as 4-layer Ti5553/Ti64/c.p.Ti (commercial purity titanium)/Ti64 is studied. The processes of formation of transition layers at the boundaries between alloys after both the smelting and the subsequent deformation by rolling, as well as after heat treatments, are studied. A relationship is established between the composition and the formed microstructure, on the one hand, and hardness, strength, ductility, and fracture under 3-point bending, on the other hand. A comparison of the titanium-layered materials produced by this method with the results provided by other technological approaches is carried out, and the advantages of the proposed technology are shown.

Porous materials are very efficient in absorbing mechanical energy, for instance, in combined armor, in order to improve the anti-ballistic protection characteristics. In the present study, porous titanium-based structures were manufactured via three different powder metallurgy methods using titanium hydride (TiH2) powder, which provided activated sintering, owing to dehydrogenation. The emission of hydrogen and shrinkage of powder particles on dehydrogenation also added an additional potential to control the sintering process and create desirable porosities. TiH2 powder was sintered with additions of NaCl or ammonium carbide as pore holding removable agents, while highly porous Ti-Al structures were formed via liquid phase reactive sintering of TiH2 and Al powders. The microstructures and porosities of sintered dehydrogenated titanium and Ti-Al structures were comparatively studied. Mechanical characteristics were evaluated using compression testing with strain rates varying from quasi-static to high levels. The resonant frequency method was also employed to determine damping parameters and elastic modulus of these materials. All testing methods were aimed at characterizing the energy-absorbing ability of the obtained porous structures. The desired strength, plasticity and energy-absorbing characteristics of porous titanium-based structures were assessed, and the possibilities of their application were also discussed. Based on the obtained results, it was found that porous titanium materials produced with the use of ammonium carbonate showed promising energy absorption properties.

Titanium alloy composites, reinforced with a light second phase and made using inexpensive powder metallurgy, attract considerable attention due to the directness of their intentional hardness increase without compromising low weight of materials. In this study the metal-matrix composites (MMC) of Ti-6Al-4V alloy reinforced with light and hard particles of TiC (up to 80%, vol.) were made using blended elemental powder metallurgy of hydrogenated titanium. Post-sintering solution treatment for 45 min. at 880 degrees C and 1000 degrees C and water quenching followed by the 5 hrs. aging at 550 degrees C was used to additionally refine the microstructure and properties of MMC. For the duration of thermal exposure throughout solution treatment and additional aging the matrix and reinforcement phase underwent distinct structural changes that modified the mechanical properties of materials. It has been shown that the used reinforcement presents an exceptional opportunity for hardening of Ti-based composites without compromising their low specific weigh. It can increase the hardness of material by more than 40% due to the ability of TiC to chemically react with the matrix to form a strong interfacial bond and its ability to form hard compounds of Ti2C and Ti3AlC in the expense of the relatively soft matrix alloy.

In this paper, a new approach for additive manufacturing metal -matrix composites based on Ti-6Al-4V titanium alloy reinforced with titanium carbide particles, as well as layered structures consisted of such composite and Ti-6Al-4V alloy layers is considered. The approach is based on 3D printing with a conical electron beam using a special cored wire, whose composition corresponds to metal -matrix composite. The issues of production such a wire, the features of the 3D printing process, when using it, as well as the features of formation of the microstructure and phase composition of the printed composite material are described. The issues of titaniumcarbide particles' wetting with Ti-6Al-4V melt during process of 3D printing, as well as possible thermogravitational effects (floating or drowning) for solid TiC particles within the melt are considered in detail with additional experiments. The influence of individual components of the wire composition on the formation of the microstructure and its uniformity over the cross section of the printed layer is shown. The possibility of controlling the formation of homogeneous structural state and obtaining sufficiently high values of the hardness (of above 600 HV) of the metal -matrix composite layer printed on the Ti-6Al-4V baseplate is shown.

Bilayer samples comprised of hard metal -matrix composite top layer and ductile 10 mm Ti-6Al-4V plate are produced with 3D printing by conical electron -beam method using specially prepared core (powder) wire that allows forming hard top layer of metal -matrix (Ti-6Al-4V) composite (MMC) reinforced by means of fine TiC particles with thickness up to 4 mm. Ballistic tests performed with 7.62 ' 51 AP ammunition show a good ballistic resistance of this protective structure, i.e., it is not perforated. Only minor penetration and partial fracture are occurred exclusively in the surface MMC layer. Either no traces of plastic deformation are found at the boundary with the base layer or inside it that indicates that the MMC layer absorbs the entire impact energy of the projectile. Based on studies of the fine structure and texture of the interface between the layers, a reasonable assumption is made that wavy geometry of MMC layer provides additional deflection and scattering of stress waves generated during impact. Comparing the results of ballistic tests of various metallic materials, it is concluded that the 3D -printed bilayer material consisting of the upper Ti-6Al-4V + 40% TiC layer and the base Ti-6Al-4V layer has an undeniable advantage in ballistic performance when it is tested with cartridges of this type.

Superior performance of laminate structures can be achieved by processing each layer individually, providing apiece layer optimal properties and further layer bonding. Layered structures of Ti-6Al-4V alloy composites reinforced with TiC or TiB particles were bond using hot isostatic pressing (HIP). The initial plates were made using blended elemental powder metallurgy (BEPM), where the amount of reinforcement was changed: 10, 20, 40% (vol.). Bonded structures were tested ballistically to evaluate their antiballistic resistance. Microstructure and properties were analyzed to understand the contribution of powder metallurgy and HIP processing to the performance of laminates. It is argued that the combination of the used two technologies, BEPM and HIP is principally complimentary for the materials in question with the abilities to solve the essential problems of each used individually.

Potential of additive manufacturing technologies, namely, xBeam 3D Metal Print-ing for the fabrication of uniform Ti-6Al-4V (Ti-6-4, mas.%) material as well as layered titanium-based structures, with mechanical properties sufficient for wide practical application is demonstrated. The key distinctive features of this process are titanium alloy wire as a feedstock material and hollow conical electron beam for heating and melting of the wire. 3D printed with special 'shift strategy' Ti-6-4 al-loy meets requirements to mechanical characteristics of corresponding conventional cast and wrought products, if microstructure features, material anisotropy and crys - tallographic texture are controlled with proper selection of processing para me ters. Production of multilayered materials consisting of combined layers of different titanium materials, viz. commercially pure titanium (CP-Ti), Ti-6-4 and high-strength T110 alloys, as well as metal matrix composites (MMC) based on Ti-6-4 matrix rein-forced by fine TiC particles is considered. Microstructural features and mechanical properties of all 3D printed materials are investigated. Terminal ballistic tests are performed with different ammunition. Described results show the promising poten-tial of 3D printing technologies, xBeam 3D Metal Printing as an example, for manu-facturing of titanium-based multilayered armour materials with reduced thickness and weight, and at the same time, sufficient protection characteristics.

Triple layer titanium-based plate consisted of Ti-6Al-4V and CP-Ti layers 3D-printed on T110 substrate was tested for antiballistic protection.Microstructure after ballistic testing, hardness and three-point flexure characteristics of the layered material were studied and analysed.Interfaces between layers are important structure features contributing antiballistic protection characteristics.3D-printed layers demonstrated sufficient bonding without porosity and other defects at interfaces, which resulted in promising antiballistic protection against high-energy B32 projectiles.Difference in microstructure, strength, hardness and ductile properties of individual layers resulted in noticeable variation of mechanical behaviour of layered materials depending on direction of applied force giving potential for further improvement of protecting characteristics.

Bilayer structures of titanium alloy Ti-6Al-4V (Ti64) and metal matrix composites (MMC) on the base of this alloy reinforced with 5, and 10 % (vol.) of TiC or TiB particles were made using press-and-sinter Blended Elemental Powder Metallurgy (BEPM). The mechanical behavior of these structures was studied under quasi-static and high strain rate compression. Dynamic tests with compression velocity in the range 4–15 m/s (820–2880 s−1) were done using the split Hopkinson pressure bar (SHPB), whereas the quasi-static tests were performed with compression velocity of 0.0005 m/s (10−3 s−1). Stress–strain curves were obtained and the effect of phase composition, microstructure, and strain rate was analyzed and discussed. Current results were compared with previous studies conducted on homogeneous MMCs and Ti64 alloy tested in similar conditions. The deformation mechanism evaluated from the microstructure analysis of the samples was verified using in-situ high-speed camera recordings. Numerical simulation based on Finite Element Analysis was conducted to further investigate the behavior of the samples during the SHPB trials. Generalized scheme of the deformation and damage process of two-layer alloy/composites hybrids as a function of compression rate was proposed.

The deformation mechanism of the Ti-6Al-4V (wt.%) alloy with globular structure was studied under conditions of quasi-static and high-strain compression with rates 10−3 s−1 and 2.1–3.3 × 103 s−1, respectively. High-strain compression was conducted using a Split Hopkinson Pressure Bar (SHPB). The details of the deformation mechanism were evaluated based on the analysis of the deformation hardening curves using the strain hardening exponent concept developed for titanium alloys in tension conditions. The used approach allowed us to identify the stages of plastic deformation observed and the controlling phase in deformation of two-phase alloy through the assessment of the strengthening index, n. It has been found that three deformation stages can be identified in quasi-static conditions. However, when the alloy is compressed at a high strain rate, the third deformation stage does not develop due to the high process rate. Further analysis of deformation curves reveals the leading role of the β-phase under the quasi-static conditions and the essential contribution of the second, α-phase, at a high compression rate. The findings on the deformation mechanism based on the analysis of hardening curves were supported by a detailed structural study.

Ti-15(wt.%)Mo alloy is produced with conventional cast and wrought approach using double electron-beam cold hearth melting, 3D hot pressing, and subsequent rolling. Three batches of specimens are subjected to microstructure study and quasi-static tensile testing in the following states: (1) as-rolled, (2) partially recrystallized via annealing at 800 degrees C for 40 minutes, (3) annealed at 800 degrees C for 3 hours followed by water quenching to fix the beta-phase. The specimens in the second state (2) are chosen for more detailed study of mechanical behaviour upon both quasi-static and high strain-rate compressions. The obtained data on the mechanical behaviour are analysed from the standpoint of the effect of initial microstructure and crystallographic texture in three mutually perpendicular planes on the strain energy and the critical strain rate that results into fracture. A detailed microstructural study of the tested specimens reveals the influence of microstructure and texture on the deformation mechanisms at different strain rates. A strong effect of microstructural inhomogeneity and crystallographic texture formed during rolling is noted. The results are compared with those obtained earlier for other titanium alloys and some important structural materials tested under the same conditions. As shown, the Ti-15Mo alloy has a rather high mechanical characteristic. At high strain rates, this material corresponds to other single-phase titanium alloys in terms of strain energy; however, it is inferior to the two-phase alloys with a fine and homogeneous microstructure, e.g., Ti-6-4 or T110 (see list of acronyms in Appendix). Taking into account the specific weight of materials, the Ti-15Mo alloy is not inferior to such high-strength materials as the heat-hardened alloy B95, steels ARMOX 600T and Docol 1500M, and, in addition, is cheaper compared to other titanium beta-alloys.

Advanced additive manufacturing technology of direct energy deposition type called x Beam 3D Metal Printing was employed for manufacturing of articles of various size and shape using titanium Ti-6Al-4V alloy wire as a feedstock material. The key distinctive feature of this process is applying of the hollow conical electron beam generated by low-voltage (< 20 kV) gas-discharge electron beam gun for heating and melting of the substrate and wire, which ensures precisely controllable liquid metal transfer from the wire end to the substrate, specific temperature gradients at the fusion area and heat flow from liquid metal pool. Such conditions of heating, melting and cooling during deposition of molten additive material provide controllable microstructure formation, including grain size and material texture. Influence of processing parameters and cooling conditions on fusion, crystallization, grain growth and intragrain structure of manufactured “chunky” Ti-6Al-4V blocks was discussed. The post-processing heat treatment was used to relieve residual stresses formed during article manufacturing. Tensile and fatigue testing has been performed for samples cut in various directions of produced articles to investigate the material uniformity. Optimization of processing parameters allowed production of 3D printed articles from Ti-6Al-4V with isotropic microstructure and mechanical characteristics which met standard requirements for Ti-6Al-4V material.

The mechanical behavior of titanium alloys has been mostly studied in quasi-static conditions when the strain rate does not exceed 10 s−1, while the studies performed in dynamic settings specifically for Ti-based composites are limited. Such data are critical to prevent the “strength margin” approach, which is used to assure the part performance under dynamic conditions in the absence of relevant data. The purpose of this study was to obtain data on the mechanical behavior of Ti-based composites under dynamic condition. The Metal Matrix Composites (MMC) on the base of the alloy Ti-6Al-4V (wt.%) were made using Blended Elemental Powder Metallurgy with different amounts of reinforcing particles: 5, 10, and 20% of TiC or 5, 10% (vol.) of TiB. Composites were studied at high strain rate compression ~1–3 × 103·s−1 using the split Hopkinson pressure bar. Mechanical behavior was analyzed considering strain rate, phase composition, microstructure, and strain energy (SE). It is shown that for the strain rates up to 1920 s−1, the strength and SE of MMC with 5% TiC are substantially higher compared to particles free alloy. The particles TiC localize the plastic deformation at the micro level, and fracturing occurs mainly by crushing particles and their aggregates. TiB MMCs have a finer grain structure and different mechanical behavior. MMC with 5 and 10% TiB do not break down at strain rates up to almost 3000 s−1; and 10% MMC surpasses other materials in the SE at strain rates exceeding 2200 s−1. The deformation mechanism of MMCs was evaluated.

Recently developed thermally hardenable medium-level alloyed titanium alloy T110 was studied from the viewpoint of microstructure influence on the mechanical behavior under quasi-static and high-strain rate deformation. The globular microstructures of two types differing in aspect ratio of α-globules were formed under thermomechanical processing conditions with different reductions (εtotal = 2, and 3) and final annealing at 850 °C, 3 h. The thermally hardened state was formed by conventional solid-solution treatment at a temperature of two-phase α+β field (880 °C, 45 min), water quenching, and final aging (550 °C, 5 h). Stress–strain dependencies were estimated on tension with strain rates varied from 8·10−4 to 4·10−2 s−1, as well as compression with a strain rate of 10−3 s−1 (quasi-static) and under high-strain rates varied from 870 s−1 to 3520 s−1; the deformation with high-strain rates has been achieved using split Hopkinson pressure bar (SHPB) technique. The tested material was also assessed using strain energy (SE) parameter. A parallel study of the microstructure and crystallographic texture formed during testing allowed to propose a reliable deformation and fracture mechanisms, depending on the stress state (tension, compression) and strain rate. A special role of the initial microstructure is noted, which determines the plasticity of the tested alloy, the sites of pore nucleation, features of crack growth, as well as the localization of deformation, which is determined by the mode and rate of loading. It is established and explained why the best balance of strength and ductility, and thus, the highest SE values in the all tests carried out were ensured by the alloy in the state with a more uniform microstructure of globular morphology (after the rolling with reduction εtotal =3), which, in turn, provided general superiority over the widely used Ti-6Al-4V alloy.

Microstructure and antiballistic protection characteristics for two types of titanium-based layered materials are studied.Binary layered armour material consisted of Ti-6Al-4V alloy and Ti-6Al-4V-10% vol.TiC metal matrix composite layers are produced using powder metallurgy and subsequent HIP treatment.Ternary Ti-6Al-4V/CP-Ti/Ti-6Al-4V armour plate is made using additive manufacturing technology.Both types of materials demonstrated a significant superiority in ballistic resistance to armor-piercing incendiary cartridges compared to uniform titanium alloys.Material microstructure and hardness, projectile penetration depth and kinetic energy are analysed to understand contribution of each layer in projectile retardation and energy dissipation.Hard front composite layer effectively retards the projectiles than softer and ductile Ti-6Al-4V and CP-Ti layers, while combination of these materials ensures lower penetration depth and absence of armour cracking on high-energy ballistic impact.