Ti6Al4V Matrix Research Articles

Achieving superior tribological properties of GNPs reinforced Ti6Al4V composites via interface structure design

The severe interface reaction, which has been a challenging problem in graphene nanoplatelets (GNPs) reinforced Ti6Al4V (TC4) matrix composites, results in poor mechanical and tribological properties. Herein, GNPs/TC4 composites exhibited excellent wear resistance by introducing the in-situ TiB whiskers (TiBw) on the interface between GNPs and matrix. This work highlights the mechanical and tribological properties of GNPs/TC4 composites by diminishing the interface reaction and strengthening the interface bonding through the in-situ formed TiBw.

In-situ synthesis of high strength and toughness TiN/Ti6Al4V sandwich composites by laser powder bed fusion under a nitrogen-containing atmosphere

Laser powder bed fusion (LPBF) additive manufacturing provides the freedom to manufacture the novel bionic structures and materials with excellent mechanical properties (e.g., combining high strength and toughness). In this work, inspired by the laminar structure of natural shells, the TiN/Ti6Al4V sandwich structural materials were fabricated in the atmosphere with different ratios of nitrogen and argon. The elemental diffusion, in-situ synthesis between N and Ti atoms, microstructure evolution, and mechanical properties of LPBF-processed TiN/Ti6Al4V sandwich composites were investigated. TiN induced by the in-situ synthesis between N and Ti atoms was observed, which exhibited an excellent metallurgical bond with the Ti6Al4V matrix. The microhardness of the TiN/Ti6Al4V layer varied from 409.62 HV0.2 and 442.55 HV0.2 with different nitrogen concentrations. The tensile strength and ductility of LPBF-processed TiN/Ti6Al4V sandwich composite parts were enhanced by the combination of bio-inspired lamellar structure and internal ceramic particle reinforcement. Interlayer hard-soft phase combination in the composite parts could be contributed to the excellent mechanical properties with an ultimate strength of 1303.12 MPa and a plastic strain of 8.9%. This study demonstrates that a flexible combination of the LPBF process and reactive atmosphere can in-situ additive manufacture the novel periodic lamellar ceramic/metal heterogeneous materials with excellent mechanical performance (e.g., rigid, wear-resistant, corrosion-resistant and toughness).

Microstructural characterization and mechanical properties of (TiB + TiC) reinforced Ti–6Al–4V prepared by melt hydrogenation

TiB and TiC reinforced Ti–6Al–4V matrix composites were prepared by melt hydrogenation, in which the total fraction of the reinforcements was 5 vol % and the ratio of TiB to TiC was 1:1. The effects of melt hydrogenation on the solidification process, phase composition, and microstructure of the titanium matrix were studied. The morphology and distribution of the reinforcement without and with hydrogen were observed. Moreover, the nano-hardness of the composites was measured. The results show that the solidification process of the matrix can be changed by melt hydrogenation, which resulting the increase of β phase and refining of α lamellar in titanium alloy. Hydrogen increased the size of the reinforcements, which aggregated at the grain boundary of the primary β phase and formed a network structure. Hydrogen reduced the nano-hardness both of the titanium alloy and the reinforcements slightly. In summary, melt hydrogenation can maintain or slightly reduce the strength of the composites at room temperature and decrease the nano-hardness.

Effect of rare earth Ce addition on microstructure and mechanical properties of titanium alloy Ti-6Al-4V

• Effect of Ce on microstructure and mechanical properties of Ti6Al4V are studied. • Ti6Al4V alloy grains are significantly refined after adding Ce. • Ce combines with O in matrix to form CeO 2 , which is coherent with the alloy matrix. • The strength and ductility of Ti6Al4V containing 0.5wt.% Ce are obviously improved. • The frictional performance of Ti6Al4V containing 0.3wt.% Ce is obviously optimized. These Ti6Al4V-xCe (x=0, 0.1, 0.3, 0.5, 0.7 wt.%) were prepared by vacuum non consumable arc furnace. And the microstructure and comprehensive mechanical properties of these Ti6Al4V were systematically explored. The results show that the tensile strength and ductility of Ti6Al4V containing 0.5 wt.% Ce is significantly improved (Ultimate tensile strength: 978.1MPa; Elongation: 7.1%). And the wear resistance of Ti6Al4V containing 0.3 wt.% Ce is significantly optimized (Wear quality: 0.55mg). The excellent balance between strength and plasticity of Ti6Al4V is due to the significant grain refinement and the complete coherent relationship between ceria and Ti6Al4V matrix.

Additive manufacturing of bionanomaterials for biomedical applications based on TI6AL4V and PLA: a systematic review

Additive manufacturing (AM) is the owner of a huge potential as a manufacturing technology in fabricating functional implants, and scaffolds for biomedical applications. AM, which includes 3D printing (3DP) and 3D bioprinting, can be the solution to produce several needs such as scaffolds/implants, tissue or organs, or medical devices by combining different biomaterials with nanomaterials. Titanium and its alloys and Polylactic acid (PLA) are commonly used in bone tissue repair with their superior bio-functionality. The rapid advancement of three-dimensional (3D) printing technology has enabled the fabrication of porous titanium and polymer composite scaffolds with controllable microstructures, which is regarded as an effective method for promoting rapid bone repair. An electronic literature search was conducted in PubMed, Web of Science, Scopus, Elsevier, Embase, and other numerous databases up to December 2021 which are accessed by Karabuk university. To evaluate the possibility of bias and methodological quality, the SYRCLE tool and the last version of the CAMARADES list were used, respectively, a meta-analysis could not be performed. This systematic review is aimed to evaluate the common biomedical potential of 3D-printed porous Ti6Al4V (Ti64) and PLA matrix scaffold for repairing bone defects to investigate the influential factors that might affect its osteogenic availability. The most ideal parameters for designing the Ti64 scaffold were found to be a pore size of around 300-400 m and porosity of 60-70%, while PLA scaffolds show 350-400 m and nearly the same percentage in porosity as Ti64.

Spark plasma forging and network size effect on strength-ductility trade-off in graphene reinforced Ti6Al4V matrix nanocomposites

Architecting tightly bonded interface microstructure is the principal guarantee for increased mechanical properties of titanium matrix composites (TMCs). Adopting an effective technique to modulate interface structure is desirable to break through the trade-off of strength-ductility. Herein, a strategy is applied to establish interlocking interface in multilayer graphene (MLG) reinforced Ti6Al4V (TC4) matrix TMCs by spark plasma sintering (SPS) with subsequent spark plasma forging (SPF). By this technique, 3D network-structured composites of 0.35 wt% MLG/TC4 with tailored network size are fabricated via varied TC4 particle sizes (2–15 μm, 15–53 μm, 63–97 μm, 120–150 μm), then their microstructure and mechanical properties are explored systematically. Results depict that enhanced interface bonding and oriented configuration of reinforcements are generated in inhomogeneous network architecture with diminished internal defects by minimizing agglomerations after deformation, simultaneously enhancing the strength and ductility. Among the different network sizes, SPFed composite with 15–53 μm TC4 powder displays the better maintained tensile ductility (ε, 10.2%) with remarkably higher yield strength (YS, σ0.2) of 1089 MPa (27.52% higher than TC4), resulting in excellent strength–ductility synergy. Strengthening mechanisms and corresponding contributions are further discussed systematically. The work provides a valuable and facile pathway to prepare high-performance TMCs with outstanding interface microstructure.

Wear Behavior of Ti6Al4V Based Hybrid Composites Reinforced with TiB2(7.5%) + TiC (7.5%)

Titanium matrix composites (TMCs) have a greater capacity to realize needs and wishes in aviation, modern firearm systems, and the locomotive sector due to the outstanding specific strength, higher temperature stability, particular stiffness, and resistance to corrosion. However, due to weak tribological characteristics and low hardness, titanium and its alloys' applicability in harsh friction and wear environments are severely constrained. The goal of this research is to improve the wear properties of Ti6Al4V-based hybrid composites reinforced with TiB2(7.5%) + TiC (7.5%). The dry sliding characteristic of powder metallurgy Ti6Al4V alloy and Ti6Al4V/ TiB2(7.5%) + TiC (7.5%) powder metallurgy composites was examined. The wear and friction behaviour of TMCs are explored utilising a pin-on-disk wear tester in a variety of circumstances. The results show that when the sliding speed increases, the particular wear rate increases as well. With the assistance of a Field Emission-Scanning Electron Microscope (FE-SEM) and Energy Dispersive Spectroscopy(EDS), the impact of TiB2 and TiC enhancement on titanium alloy microstructure as well as wear parameters were investigated. The wear resistance of the Ti6Al4V matrix was found to be increased by adding TiB2 and TiC to the sterilised Ti6Al4V matrix.

Comparative study on process-structure-property relationships of TiC/Ti6Al4V and Ti6Al4V by selective laser melting

Titanium matrix composites (TMCs) have gained tremendous attention due to their excellent mechanical properties by combining the advantages of Ti6Al4V matrix and ceramic reinforcement. In current study, the selective laser melting (SLM) technique is applied to manufacture TiC/Ti6Al4V and Ti6Al4V. Systematic characterization and analysis are conducted to reveal and compare their process-structure-property relationships. The results reveal that the near fully dense parts could be manufactured by process optimization upon the systematic investigation on their densification behaviors. The addition of TiC effectively refines the matrix grain and changes the microstructures. The SLM-manufactured (SLM-ed) Ti6Al4V exhibits typical coarse columnar grains with ultrafine lamellar α+β microstructures distributed inside (average α-lath thickness: 282 nm). Nevertheless, the SLM-ed TMCs possess a peculiar molten pool morphology, in which the sub-columnar grains grow upward along the direction of the steepest temperature gradient. The acicular nanoscale TiC is dispersed inside the sub-columnar grains, while the chain-like TiC is distributed along the boundary. Meanwhile, an evolution process is proposed to describe the microstructure evolution of the SLM-ed TMCs. The interrelationships between energy density and resulting microstructures are also identified, based on which, strong and ductile Ti6Al4V specimens (tensile strength: 1390 MPa, elongation: 9.66%) and ultra-strong TMCs specimens (tensile strength: 1538 MPa) are manufactured. The strengthening effects are mainly attributed to the Hall-Petch strengthening and load-bearing transformation. Fracture analysis indicates that the failure of the SLM-ed Ti6Al4V is caused by the micro-voids nucleation and coalescence at the interface of α and β phases, whereas the premature fracture of the SLM-ed TMCs is originated from the chain-like TiC.

Effects of GNPs on variant selection during quenching of Ti6Al4V matrix composites prepared by hot extrusion

In this work, Ti–6Al–4V matrix composites with GNPs distributed along the extrusion direction(ED) were prepared by hot extrusion, and the effect of GNPs on variant selection of Ti6Al4V alloy during quenching was investigated. The electron backscatter diffraction (EBSD) data showed that GNPs induced variant selection of Ti–6Al–4V, resulting in a difference in the texture intensity distribution of basket-woven α phase in the transverse direction (TD). The contents of various variants in a single grain were analyzed statistics, and the volume changes caused by the variants were calculated. The results show that the interfacial stress of GNPs increases the content of α variants whose volume expansion direction is consistent with the expansion direction of GNPs.

The Microstructural Properties and Tribological Performance of Al2O3 and TiN Nanoparticles Reinforced Ti–6Al–4V Composite Coating Deposited on AISI304 Steel by TIG Cladding

Abstract This investigation presents the tribological performance of (Al2O3 + TiN)/Ti6Al4V cladding deposited on AISI304 steel substrate by the tungsten inert gas (TIG) cladding approach. The microstructural characterization by SEM confirmed claddings with visually crack-free and sound metallurgical bonding at the clad layer—substrate interface. The energy dispersive spectroscopy (EDS) analysis revealed the presence of matrix and reinforcement phases as major elements with the clad layer and with considerably no oxidation during their deposition. The XRD spectra revealed that matrix and reinforcements are dominant phases in the clad layer. The formation of compounds reflected considerably a lower dilution of reinforcement phase with Ti6Al4V matrix during melting and deposition. Higher the microhardness of the (Al2O3 + TiN)/Ti6Al4V clad layer in the cladding zone compared with other clad layer compositions such as Ti6Al4V, Al2O3/Ti6Al4V, and TiN/Ti6Al4V, it is varied from 1130HV0.2 to 1222HV0.2, and the average microhardness is about 990.57HV0.2 which is 175% improvement compared with the substrate. The cladding with dual reinforcement composition has shown a superior wear resistance compared with all other clad layer composite compositions. The improvement in the wear resistance achieved with (Al2O3 + TiN)/Ti6Al4V composite clad layer deposition at 2.5 m/s, 3.5 m/s, and 4.5 m/s sliding velocities is 56.60%, 63.26%, and 68.53%, respectively, compared with the substrate. The wear morphology of the composite claddings is relatively smoother and the wear furrows are shallower compared with the substrate, especially for the composite clad layer with (Al2O3 + TiN) reinforcement phase.

Wire arc additive manufacturing of network microstructure (TiB+TiC)/Ti6Al4V composites using flux-cored wires

Titanium matrix composites (TMCs) with ceramic particles exhibit higher hardness, strength, and wear resistance than those of titanium alloys. Wire arc additive manufacturing (WAAM) is a promising method for fabricating large TMC components owing to its high deposition rate and low production cost. In this study, a WAAM process using a flux-cored wire was developed to fabricate components of TiB plus TiC reinforced Ti6Al4V matrix composites. The network microstructure of the reinforcement was obtained through in-situ reactions induced by the B4C and C powders in the flux core. The formation mechanism of the network microstructure was discussed. The effect of the reinforcement fraction (5 and 10 wt%, hereinafter called 5 and 10 wt% samples) on the microstructure and wear resistance of the samples along the deposition direction were investigated. The results showed that the refined net-basket-dominated (α＋β)-Ti matrix and stable network microstructure were formed in middle region owing to the introduction of the reinforcement. The microhardness increased by 23% and 35% when the reinforcement fractions were 5 and 10 wt%, respectively. The 10 wt% sample showed reduced wear performance because more cracks appeared as the result of the decreased ductility.

In-situ dual-deoxidation design of advanced titanium matrix composites by pressureless sintering

We establish a methodology of in-situ dual-deoxidation to fabricate advanced titanium matrix composites (TMCs) by pressureless sintering (PLS). Specifically, the in-situ dual-deoxidation of impurity O in Ti matrix was designed as the in-situ formation of H2O and La2O3 particles, which was accomplished by PLS of advanced TMCs from powder mixtures containing Ti–6Al–4V matrix of TiH2 and 60Al40V together with LaB6 addition. Interestingly, the advanced TMCs with in-situ La2O3 particle and TiB whisker have various merits, including the significantly reduced O content in the Ti matrix, the refined equiaxed α-Ti grain with monolayer nanosized L phase grain boundary, and especially the nearly full-density evading Kirkendall's pore. Resultantly, the advanced TMCs circumvent the strength–ductility trade-off of representative Ti–6Al–4V TMCs by various materials processing methods. Our results provide a novel strategy for fabricating cost-effective advanced TMCs by PLS to yield superior mechanical properties.

Microstructure and mechanical properties of GNPs and in-situ TiB hybrid reinforced Ti–6Al–4V matrix composites with 3D network architecture

Graphene nanoplatelets (GNPs) and TiB whiskers (TiBw) hybrid reinforced Ti–6Al–4V (TC4) matrix composites ((GNPs + TiBw)/TC4) were fabricated by Fast Hot-Press Sintering (FHPS) and hot rolling (HR) method. The microstructure, mechanical properties and strengthening mechanisms were systematically studied with various TiBw contents. Microstructure observation results indicate that GNPs can be mostly preserved and TiBw are rarely obtained during the sintering process. HR process was applied to further densify the composites and obtain the in-situ TiBw. The high ductility of composites was achieved via designing network structure with reinforcements of GNPs and in-situ TiBw, which reduce the interface reaction of the GNPs/Ti and improved the interface bonding. The tensile ductility of the GNPs/TC4 composites were improved with the addition of TiB2 powders. As a result, 0.1 wt% GNPs/TC4 composites with the addition of 0.05 wt% TiB2 powders showed the best combination of ultimate tensile strength of 1158 MPa and a fracture elongation of 15.8%. Compared to the fracture elongation of pure TC4 alloy (15.2%), there was no sacrifice of ductility.

Titanium matrix composites reinforced with biogenic filler

Novel metal matrix composites (MMCs) have been fabricated with Ti6Al4V matrix and a biogenic ceramic filler in the form of diatomaceous earth (DE). Mixtures of DE and Ti6Al4V powders were consolidated by the spark plasma sintering (SPS) method. Microstructure of the consolidated samples has been investigated with microscopic techniques and XRD. Thermomechanical characteristics have been obtained using small-sample techniques. The results obtained indicate that the fabricated composites show outstanding mechanical and thermal properties due to synergic effects between the filler and the matrix (beyond the rule of mixtures).

Ti6Al4V/SiC Metal Matrix Composites Additively Manufactured by Direct Laser Deposition

Nowadays, research on additive manufacturing of Ti6Al4V alloy is growing exponentially but there are just a few studies about additive manufacturing of metal matrix composite components. In this work, highly reinforced Ti6Al4V matrix composites with SiC particles have been additively manufactured by direct laser deposition (DLD). Ti6Al4V powder and SiC particles have been deposited layer by layer to form an additive thin wall structure. The geometry, microstructure, and microhardness of the samples are strongly influenced by the laser scanning speed used during de fabrication process. In addition, the effect of the SiC increment in reinforcement concentrations and the influence of SiC particle sizes in the microstructure have been evaluated, and the reaction mechanisms have been established. The percentage of reinforcement measured is lower than expected due to the reinforcement-matrix reactivity that results in partially dissolved SiC particles and the formation of a TiC and Si5Ti3 ring around them. The size and number of particles and reaction products depend on the initial size and percentage of reinforcement and the DLD scanning speed. The higher the size and percentage of SiC particles and reaction products in the matrix, the higher the hardening effect of the composite matrix.Graphic

Interface configuration effect on mechanical and tribological properties of three-dimension network architectural titanium alloy matrix nanocomposites

Strong interfacial bonding is the primarily crucial issue in titanium matrix composites (TMCs). In this study, three-dimensional (3D) network structured Ti6Al4V (TC4) matrix TMCs with 0.15 wt% few-layer graphene (FLG) were fabricated by high pressure spark plasma sintering (SPS, 200–300 MPa) at 850 ℃, 900 ℃ and 950 ℃, correspondingly producing three types of interface configuration with in-situ TiC to FLG ratio of 4:6, 7:3 and 9:1. Composites sintered under 900 ℃ displayed outstanding integrated properties, including high micro-hardness (345.2 HV), excellent ultimate tensile strength (UTS, 1041 MPa) with acceptable tensile ductility (ε, 9.3%) and wear resistance with the lower wear rate (ω, 5.3 × 10−4 mm3/Nm). The synergistic effect of moderately generated TiC reinforcements on FLG (ratio of 7:3) in 3D network boundary under 900 ℃ leads to efficient load-bearing capacity, acting as the dominant strengthening mechanism. Self-lubricating effect of FLG and debris strengthening of TiC and TiO2 are also responsible for improved wear resistance.

Ti6Al4V matrix composites fabricated by laser powder bed fusion in dilute nitrogen

In situ synthesised TiN reinforced Ti6Al4V matrix composites were fabricated via laser powder bed fusion (L-PBF) in an atmosphere of 10vol.-% N2 and 90vol.-% Ar based on novel gas–liquid reaction between N2 and Ti6Al4V melt pool. With lower laser energy density (LED), the microstructures of the composites mainly consisted of acicular α′ martensites, while the martensites were shortened and coarsened with increasing LED. The X-ray diffraction analysis demonstrated that the interstitial solid solution of N was formed in the Ti lattice. High-resolution transmission electron microscopy analysis confirmed the generation of TiN. The microhardness, yield strength, ultimate strength and plasticity of the composites initially increased and then decreased with increasing LED. The strengthening mechanisms of the composites were elucidated.

Visual assessment of special rod-like α-Ti precipitates within the in situ TiC crystals and the mechanical responses of titanium matrix composites

TiC crystals are an ideal and irreplaceable reinforcement in metal matrix composites (MMCs). The C, Ti vacancies and dislocations provide elemental diffusion channels, and thermal processing provides sufficient activation energy to induce a special rod-like α-Ti phase, even the phase transformation of β-Ti→α-Ti within the in situ TiC crystals. The ultimate tensile strength of the 8 vol % TiC/Ti6Al4V at 723K increase by approximately 12.6%, and the fatigue crack at 723K grows much faster than the Ti6Al4V matrix, which is nearly 2 times. The rod-like α-Ti imposes an additive effect on the stress concentration within the TiC crystals during deformation, and results in the formation of microcracks and microvoids within the TiC crystals, ultimately, the premature fracture of TiC crystals, thus, reducing the strengthening effect on the TMCs and accelerating the fatigue crack propagation . To prevent effectively rod-like α-Ti precipitates within the TiC crystals and improve the tensile properties and fatigue performances, the TiC content should be reduced as much as possible (lower than 2.5 vol %), and its size should be as small as possible (smaller than 10 μm). Our work provides strong evidence for atomic diffusion within the in situ TiC crystals and paves the way to make full use of the strengthening effect of TiC crystals on MMCs. • C vacancies, Ti vacancies, and dislocations within the TiC crystals serve as atomic diffusion channels, and the diffusion of Al, V and C atoms result in special rod-like α-Ti precipitates within in situ TiC crystals. • Phase transformation of β.→α occurs in the TiC crystals, and they obey ORs <11 2 ‾ 0> α //<110> TiC //<111> β and {0001} α //{111} TiC //{110} β . • The rod-like α-Ti precipitates impose an additive effect on the stress concentration within the TiC crystals, reducing the strengthening effect on the TMCs. • Different deformation abilities, coefficients of thermal expansion, and hardness resulted in the formation of microvoids and microcracks within the TiC crystals, even the cleavage fracture along {100}, {110} and {111} planes.

In Situ Ti6Al4V/TiB Composites Prepared by Hydrogen-Assisted Sintering of Blends Containing TiH2 and Ball-Milled Ti+TiB2 Powders.

In the present study, 98.6–99.5% dense in situ reinforced Ti6Al4V/TiB composites were manufactured with a newly developed approach based on hydrogen-assisted blended elemental powder metallurgy (BEPM). The approach includes the activation milling of titanium powder produced with hydrogenation-dehydrogenation (HDH-Ti powder) with finer TiB2 additives, following blending with TiH2 and master alloy (MA) powders, and final press-and-sinter operations. Scanning electron microscope (SEM) observations prove the formation of microstructures with improved density and homogeneous distribution of TiB reinforcements in a sintered Ti6Al4V matrix. Hardness and compressive tests validated the high mechanical characteristics of produced composites. The effect of preliminary milling time over 2–6 h and the ratio of hydrogenated and non-hydrogenated titanium powders used (TiH2 vs. HDH Ti) on microstructure and mechanical properties were studied to further optimize the processing parameters. Test results indicate the above approach can be regarded as a promising route for the cost-effective manufacturing of Ti6Al4V/TiB composite with reduced porosity, tailored microstructure uniformity, acceptable impurity level and, hence, mechanical characteristics sufficient for practice applications.

Nanoparticulate reinforced composites and their application to additively manufactured TI6AL4V for use in the aerospace sector

Metal matrix composites possess good mechanical properties at high temperatures making them good candidates for components that operate in conditions of high temperatures where they have to withstand static creep and cyclic fatigue loads. The mechanical properties of Ti6Al4V including hardness, strength, modulus of elasticity, and wear resistance can be enhanced with nano particulates to obtain lighter and stronger materials that can function at elevated temperatures. This paper starts with a brief background on composite materials and then turns to analysis of carbon nanotubes, titanium carbide, silicon carbide, titanium boride, titanium diboride, and titanium nitride nano particulate materials as candidates for the reinforcement for Ti6Al4V to form composites for aerospace applications. Based on a comparison of their physical properties of melting point, coefficient of thermal expansion, density and mechanical properties of strength, Young's modulus and hardness all obtained from literature, the paper narrows down on multiwalled carbon nanotubes and titanium diboride as the preferred nano composites for this use. Presently, experimental work is under way to determine optimum process parameters for additively built carbon nanotube/Ti6Al4V composites that will be used to build three-dimensional specimens for testing to determine their mechanical properties. This is expected to clarify the value of incorporating the carbon nanotubes in the Ti6Al4V matrix with respect to selected mechanical properties. Future work is envisaged on additively build titanium diboride/Ti6Al4V composites to the same end and in order to determine which of the two nano particles is best in enhancing the mechanical properties of Ti6Al4V.