TiB2 Nanoparticles Research Articles

Laser powder bed fusion of nano-TiB2 reinforced FeCoNiCr high-entropy alloy with enhanced strength and firm corrosion resistance

FeCoNiCr high-entropy alloys have excellent corrosion resistance and low absolute strength. By adding TiB2 nanoparticles, FeCoNiCr high-entropy alloy composites produced via laser powder bed fusion was reinforced, it possessed the excellent structural stability of TiB2 and FeCoNiCr matrix, and its lattice was face center cubic without component segregation. The nanoparticles have positive influences on mechanical properties and corrosion resistance. The second-phase strengthening and the fine-grain strengthening sourcing generated by the nucleation effect of nanoparticles and the process characteristics of the laser powder bed fusion enhanced the strength. The nanoparticles induced grain refinement to reduce the electrochemical corrosion rate of the composite in 3.5 wt% NaCl solution, while the nanoparticles were easy to damage the passive film. The lower corrosion rate contributes greatly to the improvement of the corrosion resistance of the composite.

Formation mechanism of TiB2 nanoparticles and development of TiB2p/6201 nanocomposites as a neoteric conducting material

TiB 2 nanoparticles were fabricated by the melt reaction between Al-10Ti and Al-3B master alloys. The reaction mechanism is ascribed to the decomposition of Al 3 Ti to release free Ti atoms, which diffuse across the AlB 2 /Al interface and substitute the Al atoms to form TiB 2 . This substitution produces a layer of pseudo-TiB 2 on the prism planes {10‐10} AlB2 firstly, which has the same lattice structure and the similar values of the lattice parameter as AlB 2 . It follows the fact that the nucleation occurs at the prism planes {10‐10}. Subsequently, the epitaxial transformation of TiB 2 particles is initiated inward the pseudo-TiB 2 , which becomes detached from the substrate owing to the crystallographic mismatch between the two, thus forming the TiB 2 nanoparticles. The exposed AlB 2 prism surfaces continue to react with Ti atoms until they are totally consumed. Increasing the reaction temperature, prolonging the holding time could improve the extent of reaction, thus increasing the electrical conductivity and reducing the elastic modulus. Especially, the effects of ultrasonic vibration treatment (UVT) on the reaction process were explored. Cavitation and acoustic flow generated by UVT showed a magnificent potential for promoting the reaction in melts. Thanks to the interface reaction, nano-TiB 2 particles can be generated. The nano-TiB 2p /6201 composites produced by this method recorded significant improvement in the tensile properties. • Nano-TiB 2 particles are generated on the prism planes of micron AlB 2 particulates. • Reaction mechanism of born treatment is revealed at the atomic scale. • The reaction is effectively accelerated by ultrasonic vibration treatment.

Effects of TiB2 nanoparticles and ultrasonic vibration on the mechanical properties of an Mg-4Al-1.5Si alloy

3 vol% TiB2 nanoparticles were added to an Mg-4Al-1.5Si alloy through semi-solid stirring followed by ultrasonic vibration to refine coarse Mg2Si phases. The effect of the added TiB2 nanoparticles on the size and morphology of the Mg2Si phases as well as the mechanical properties of the magnesium alloy was investigated. The experimental results showed that under the synergistic action of ultrasonic vibration and heterogeneous nucleation of TiB2 nanoparticles, the primary Mg2Si phases were not only refined from coarse dendritic to fine blocky shape but also uniformly dispersed. The morphology of the eutectic Mg2Si phases was transformed from coarse Chinese scripts to fine short strips. The Vickers-hardness, ultimate tensile strength, and yield strength of the obtained composites were increased by 101.8%, 69.8%, and 10.6%, respectively, compared with the matrix alloy, and the elongation was enhanced from 3.2% to 9.2% especially. The fracture mode was transformed from brittle fracture of the untreated Mg alloy to ductile fracture of the composites, indicating that the TiB2 nanoparticles play an effective role in strengthening and toughening Mg-Al-Si alloys.

Versatility of trace nano-TiC–TiB2 in collaborative control of solidification-rolling-welding microstructural evolution in Al–Mg–Si alloy for enhanced properties

It is challenging to concurrently control the microstructure evolutions after undergoing casting, sheet forming and welding. This study successfully addressed this challenge via trace TiC–TiB2 nanoparticles in the amelioration of solidification-rolling-welding microstructural evolution. Nanoparticles refined the solidified microstructures and significantly increased the net driving force for recrystallization, promoting the precipitation of nanoscale Guinier–Preston zones and β'' phases. The coarsening of the fusion and heat-affected zones was also effectively suppressed. The yield strength (YS) and ultimate tensile strength (UTS) of the rolled plates were enhanced by 31.3% and 16.3%, respectively, without significantly sacrificing ductility. Additionally, the YS and UTS of the as-welded welding joints were enhanced by 30.2% and 7.8%, respectively. The amelioration mechanism of TiC–TiB2 throughout the microstructural evolution and strengthening process was systematically investigated. This study provides a typical model for the complete amelioration of microstructural evolution in aluminum alloys under multiple processing conditions.

Electrochemical origin for mitigated pitting initiation in AA7075 alloy with TiB2 nanoparticles

High-strength Al alloys are susceptible to various corrosion degradation, and the notorious pitting process is the major source for catastrophic failures. Recent development of metal nanocomposites may overcome some of these degradation issues, but the mechanism is unclear due to the blurred pitting initiation and evolution. In this paper, we have systematically analyzed the microstructural change induced by TiB2 nanoparticle nano-treating in AA7075 alloy. The pitting initiation process is directly observed, and the high-resolution surface topographies are used to compare pits’ size and density. Pitted surfaces after long-term immersion are characterized by XPS to quantify the surface composition evolution. Considering these distinct microstructures and surface features, a potential-determined electrochemical model has been set up to explain this advantageous role of TiB2 nanoparticles in AA7075, and our results confirm that this understanding is ubiquitous even with other suitable ceramic nanoparticles.

Corrosion behavior of nano-treated AA7075 alloy with TiC and TiB2 nanoparticles

High-strength Al alloys like Al-Zn-Mg-Cu series are susceptible to corrosion attacks. Nano-treating is an emerging metallurgical method to enhance their performance. However, there lacks an understanding of nanoparticles’ effects on their corrosion. In this study, corrosion performance of two nano-treated cast and extruded AA7075 alloys (with TiC and TiB2) was investigated. Their dynamical corrosion characteristics on freshly exposed, passivated, and immersed surfaces were compared. The interplays among microstructures, oxidation passivation, and corrosion were revealed. The results show nano-treating enhances corrosion resistance of AA7075, particularly localized corrosion resistance. This study has advanced the multi-scale understanding of corrosion in nano-treated AA7075.

An investigation on microstructure and mechanical behaviour of aluminium hybrid metal matrix nanocomposite fabricated through electromagnetic stir casting process

This study focuses on the microstructure characteristics and mechanical properties of unreinforced and reinforced ceramic materials titanium diboride (TiB2) and graphite (Gr). Aluminium hybrid metal matrix nanocomposites reinforced with varying weight percentage of nano TiB2 (0-12.5 wt. %) and nano Gr (4wt %) via electromagnetic stir casting process to produce hybrid nanocomposites samples. Identification of phases and microstructure analysis are performed through X-ray diffraction, Optical Microscope and Scanning Electron Microscope with Energy Dispersion X-ray Spectrum. Mechanical properties such as hardness, tensile, compression and flexural strength were investigated on the prepared hybrid nanocomposites samples. Microstructure images of the samples reveals uniform dissemination of reinforced TiB2 and Gr nanoparticles in Aluminium base matrix and X-ray diffraction confirms the presence of reinforced particles TiB2 and Gr in Aluminium base matrix. Concluded from the consolidated samples, mechanical properties of the reinforced samples improved as compared to the matrix material.

The microstructure evolution and precipitation behavior of TiB2/Inconel 718 composites manufactured by selective laser melting

Additive Manufacturing is an advanced material processing technology emerging in recent years. However, coarse columnar grain structure of additive manufactured metals reduces the performance of the material. Facilitating the columnar to equiaxed transition (CET) has become a research hotspot. In this paper, the equiaxed grain of additive manufactured Inconel 718 was achieved by adding TiB2 particles. Simultaneously, the microstructure evolution and precipitation behavior with nano-TiB2 particles addition were studied. The results show that the grain morphology of Inconel 718 exhibited coarse columnar grains with epitaxial growth and strong <100> texture. When 3 wt% TiB2 was added, the columnar grains became finer, further increased the content of TiB2 to 5 wt%, the equiaxed grains were obtained and the texture intensity decreased significantly. In addition, TiB2 partially melted under the high laser energy changed the phase precipitation behavior of Inconel 718 from chain-like Laves phase to reticulated (γ + M3B2) eutectics, which lead to the hardness increased from 276 HV to 578 HV when 5 wt% TiB2 was added. After heat treatment, the precipitation of high density γ′ and γ″ strengthening phase were promoted the hardness increased by 87% to 516 HV in Inconel 718. However, the hardness of TiB2 reinforced samples showed a little change, which could be attributed to the partial dissolution of M3B2 boride during the heat treatment.

Enhancing strength and ductility of AlSi10Mg fabricated by selective laser melting by TiB2 nanoparticles

• Introduced nano-TiB 2 achieves CTE transition, grain refinement and texture elimination. • The strength and ductility are improved simultaneously by the nano-TiB 2 particles. • The influence mechanisms of the nanoparticles on ductility are clarified. In the metallic components fabricated by the emerging selective laser melting (SLM) technology, most strategies used for strengthening the materials sacrifice the ductility, leading to the so-called strength-ductility trade-off. In the present study, we report that the strength and ductility of materials can be enhanced simultaneously by introducing nanoparticles, which can break the trade-off of the metallic materials. In the case of in-situ nano-TiB 2 decorated AlSi10Mg composites, the introduced nanoparticles lead to columnar-to-equiaxed transition, grain refinement and texture elimination. With increasing content of nanoparticles, the strength increases continually. Significantly, the ductility first increases and then decreases. Our results show that the ductility is controlled by the competition between the crack-induced catastrophic fracture and ductile fracture associated with dislocation activities. The first increase of ductility is mainly attributed to the suppression of crack-induced catastrophic fracture when TiB 2 nanoparticles present. With the further increase of TiB 2 nanoparticles, the subsequent decrease of ductility is mainly controlled by dislocation activities. Thus, the materials will exhibit the optimum strength and ductility combination in a certain range of TiB 2 nanoparticles. This study clarifies the physical mechanism controlling ductility for nano-TiB 2 decorated AlSi10Mg composites, which provides the insights for the design of structural materials.

Fabrication of TiB2 coatings by electrophoretic deposition of synthesized TiB2 nanoparticles in molten salts

This paper presents a novel process for preparation of TiB2 coatings, which is a combination of synthesis of TiB2 nanoparticles by borothermal reduction of TiO2 in molten NaCl–KCl–AlF3 system and subsequent electrophoretic deposition of the as-synthesized TiB2 nanoparticles in the same molten salts system. The electrophoretic deposition under various cell voltages was carried out, which resulted in preparation of dense and relatively flat TiB2 coatings. The effect of applied cell voltages on the electrophoretic deposition rate and mechanical properties of produced TiB2 coatings has been presented. The thickness of the coatings increased with the rise of cell voltages due to elevated migration and deposition rate of TiB2 nanoparticles. The hardness of the fabricated TiB2 coatings was assessed by nanoindentation, indicating that the values of hardness and elastic modulus increased with elevated electrophoretic voltages, which probably has an influence on the structure of the TiB2 coatings. Under the cell voltage of 1.2 V, the values of hardness and elastic modulus could reach 32.4 ± 1.2 GPa and 420.2 ± 23.9 GPa, respectively. This proposed process should also be applied for preparation of additional types of transition metal diboride coatings.

Effect of in-situ TiB2 particles on microstructure and mechanical properties of Al–Fe–Ni manufactured by selective laser melting

To simultaneously enhance the strength and ductility of novel heat-resistant Al–Fe–Ni alloy manufactured by selective laser melting (SLM), nano-TiB2 particles are introduced to break the strength-ductility trade-off. In this study, in-situ TiB2 decorated Al–Fe–Ni composite and Al–Fe–Ni base alloy have been successfully fabricated by SLM to investigate the effects of TiB2 particles on the microstructure and mechanical properties. The results showed that broader SLM process windows and higher relative densities (better SLM processability) were achieved in the composite. The introduced TiB2 particles transformed the large elongated grains with a strong {100} texture in the Al–Fe–Ni alloy to fine equiaxed grains with random orientation in the TiB2/Al–Fe–Ni composite. The morphology and distribution of Al9FeNi phases were also changed due to the existence of particles. The stress-strain curves obtained from tensile tests showed that the strength and ductility were improved simultaneously in the composite compared with those in the alloy. The underlying mechanisms of strengthening and enhancing ductility are preliminarily elucidated.

Molecular Genetics and Cytotoxic Responses to Titanium Diboride and Zinc Borate Nanoparticles on Cultured Human Primary Alveolar Epithelial Cells

Titanium diboride (TiB2) and zinc borate (Zn3BO6) have been utilized in wide spectrum industrial areas because of their favorable properties such as a high melting point, good wear resistance, high hardness and thermal conductivity. On the other hand, the biomedical potentials of TiB2 and Zn3BO6 are still unknown because there is no comprehensive analysis that uncovers their biocompatibility features. Thus, the toxicogenomic properties of TiB2 and Zn3BO6 nanoparticles (NPs) were investigated on human primary alveolar epithelial cell cultures (HPAEpiC) by using different cell viability assays and microarray analyses. Protein-Protein Interaction Networks Functional Enrichment Analysis (STRING) was used to associate differentially expressed gene probes. According to the results, up to 10 mg/L concentration of TiB2 and Zn3BO6 NPs application did not stimulate a cytotoxic effect on the HPAEpiC cell cultures. Microarray analysis revealed that TiB2 NPs exposure enhances cellular adhesion molecules, proteases and carrier protein expression. Furthermore, Zn3BO6 NPs caused differential gene expressions in the cell cycle, cell division and extracellular matrix regulators. Finally, STRING analyses put forth that inflammation, cell regeneration and tissue repair-related gene interactions were affected by TiB2 NPs application. Zn3BO6 NPs exposure significantly altered inflammation, lipid metabolism and infection response activator-related gene interactions. These investigations illustrated that TiB2 and Zn3BO6 NPs exposure may affect different aspects of cellular machineries such as immunogenic responses, tissue regeneration and cell survival. Thus, these types of cellular mechanisms should be taken into account before the use of the related NPs in further biomedical applications.

Selective laser melting of 7075 aluminum alloy inoculated by Al–Ti–B: Grain refinement and superior mechanical properties

Coarse column grain and hot cracking severely hinder the application of AA7075 aluminum alloy fabricated by selective laser melting (SLM). In this work, a novel grain refiner consisting of submicron TiH2 and amorphous B particles was developed to control such features in SLM-fabricated AA7075 alloy. Crack-free and dense (TiH2+B)/AA7075 alloy was fabricated under optimal SLM processing. Results show that the addition of TiH2 and B particles can convert coarse columnar grains into homogeneous equiaxed grains, decrease the average grain size from 29.1 μm to 2.3 μm, and consequently eliminate the hot-cracking in (TiH2+B)/AA7075 alloy. The remarkable grain refinement is mainly attributed to heterogeneous nucleation promoted by a combination of in-situ formed L12-Al3Ti and TiB2 nanoparticles. After T6 heat treatment, the (TiH2+B)/AA7075 alloy behaves superior mechanical properties(tensile strength of ∼582 MPa and ductility of ∼12.8%) to most previously reported SLM-fabricated 7075 alloys. Synergetic effects of crack elimination, grain refinement, and precipitation strengthening are responsible for the excellent mechanical properties.

Ultrasound-assisted dispersion of TiB2 nanoparticles in 7075 matrix hybrid composites

Refinement and dispersion of rigid ceramic particles enhance the mechanical properties of particulate reinforced aluminum matrix composites (PRAMCs). However, nanoparticles are intrinsically clustered or agglomerated together in melts and thereby reduce their strengthening efficacy. Ultrasound cavitation and acoustic streaming can effectively improve the distribution of nanoparticles in melts. In this work, we use synchrotron radiation X-ray computed tomography (SR-CT) to unveil the particle dispersion mechanism by ultrasound vibration treatment (UVT) from three-dimensional perspective. The SR-CT results indicated that the mesoscale agglomerates in a high-strength 7075 aluminum alloys can be eliminated completely upon UVT. Two types of TiB2 particles have been identified, termed as micro-size TiB2 particles (MTPs) and nano-size TiB2 particles (NTPs), which were observed to be aggregated along the grain boundaries and dispersed uniformly within the α-Al grains, respectively. Tensile tests reveal significant strengthening of the composites in the as-cast state, suggesting effective Orowan strengthening. This strength enhancement is attributed to the dispersed NTPs that have been retained after solidification. It is also inspiring to see the concurrent increase in the ductility of the composites after UVT, thanks to the improvement in particle distribution.

Microstructure and mechanical properties of in-situ dual morphology Ti8C5/TiB2 reinforced TiAl composite

An in-situ dual morphology Ti8C5/TiB2 reinforced TiAl composite (DMTTC) is prepared by adding the inoculant which is prepared by spark plasma sintering (SPS). In DMTTC, Ti8C5 whiskers/nanoparticles and TiB2 nanoparticles have a synergistic strengthening effect on TiAl alloy. In addition, this paper further discusses the synergistic strengthening mechanism of DMTTC.

Influence of titanium diboride and graphite on microstructure characteristics and mechanical behaviors of aluminium hybrid nanocomposites

The present work investigates the influence of graphite (Gr) on microstructure and mechanical behaviour of Al7075/TiB2/2wt%Gr hybrid nanocomposite. Aluminium matrix hybrid nanocomposites (AMNCs) were fabricated using electromagnetic stir casting technique. The hybrid nanocomposites were characterized by optical Microstructure (OM), X-ray Diffraction (XRD), Energy Dispersive X-ray Spectrum (EDAS) and Scanning Electron Microscope (SEM). The Al7075/TiB2/Gr hybrid nanocomposties was prepared with 2 wt% Gr nanoparticles addition and 2.5, 5, 7.5, 10 and 12.5 wt% of TiB2 nanoparticles. Results revealed that with the addition of reinforcement hardness of nanocomposties were increased by 145.42BHN to 173.48BHN. Significant improvements in tensile strength, compression strength and flexural strength of AMNCs were attained upto10 wt% TiB2 addition, further decrease in strength at 12.5 wt% TiB2 addition in Al7075 and Al7075 alloy. Considerable enhancement in mechanical properties shows homogenous distribution and agglomerated along the grain boundaries decreases the mechanical properties of the reinforced nanoparticles in the matrix.

Enhancement of Wear Resistance on H13 Tool and Die Steels by Trace Nanoparticles

In order to improve the impact toughness and wear resistance of the tool and die steels, this study innovatively prepared strengthened H13 steels with different contents of single-phase TiC and dual-phase TiC + TiB2 through in situ nanoparticle/Al master alloys at room temperature. The microstructure evolution and mechanical properties as well as wear resistance were investigated. Results indicate that the H13 steel with 0.02 wt.% dual-phase TiC + TiB2 nanoparticles has a more uniform and finer microstructure, and the mechanical properties and wear resistance are significantly improved. The yield strength, maximum tensile strength, breaking strain, uniform elongation, product of strength plasticity, and unnotched and U-notched impact toughness of H13 steel with 0.02 wt.% dual-phase TiC + TiB2 are higher than that of H13 steel. In addition, the volume wear rate, maximum scratch depth and width reach 7.1 × 10−11 m3/m, 6050 nm and 90 μm, respectively, which are reduced by 44.5%, 30.1% and 45.5% compared with that of H13 steel. Refining the microstructure and improving impact toughness and wear resistance of H13 tool steel through trace nanoparticles can provide important inspiration for industrial applications.

Ultrasonic effects on gas tungsten arc based wire additive manufacturing of aluminum matrix nanocomposite

This study focused on a newly developed ultrasonically assisted (UA) wire arc additive manufacturing (WAAM) process for metal matrix nanocomposite of AA7075 with TiB2 nanoparticles. The ultrasonic probe was directly dipped into the local molten pool and traveled behind the arc during deposition. Comprehensive experimental studies were performed and the UA-WAAM sample showed superiorities over conventional WAAM ones in multiple perspectives including a lower number of porosities, refined solidification structure, and less agglomerated nanoparticle distribution under the same deposition parameters. These improved microstructure features led to enhanced mechanical properties of the UA-WAAM samples, as reflected in the tensile tests and hardness measurement results. The benefits of nanoparticles in the formation of equiaxed grain structures and strength contribution was further leveraged by UA based on their better dispersion. The ultrasonic effects on WAAM process can be mainly attributed to the two nonlinear physical phenomena: acoustic cavitation and streaming induced by power ultrasound in molten metal.

Synthesis of AA8050/B4C/TiB2 Hybrid Nanocomposites and Evaluation of Computer‐Aided Machining Parameters

This research focusses on synthesizing the hybrid nanocomposite samples with AA8050 and the reinforcement of B4C and TiB2 nanoparticles at 3 different quality grades. To investigate their machinabilities on the prepared composites in the computer‐aided machining centre, the objectives are maximizing the material removal rate (MRR) and minimizing the surface roughness for a specific application. Stir casting process was employed in synthesizing the hybrid nanocomposite samples. Utilizing CNC turning centre was employed to investigate machinability performance on hybrid nanocomposite samples. The PVD‐coated HSS tool and dry cutting environment were considered. The quality of machining was investigated by observing the surface roughness on the machined surfaces of samples of hybrid nanocomposite. The machining rate was investigated through the response of material removal rate at as per Taguchi design of experiments L27 orthogonal array. The hybrid nanocomposite synthesizing parameter of contribution of nanoparticle reinforcement (8%, 10%, and 12%) and the Turing parameters include spindle speed (800 rpm, 1000 rpm, and 1200 rpm), machining feed (0.05 mm/rev, 0.10 mm/rev, and 0.15 mm/rev) and depth of cut (0.5 mm, 0.75 mm, and 1 mm). The best performing input levels were identified through Taguchi analysis and the involved input variables were analysed and prediction model developed through ANOVA. The maximum material removal rate and the minimum surface roughness were reordered as 1380 mm3/min.

Analysis of Spectroscopic, Morphological Characterization and Interaction of Dye Molecules for the Surface Modification of TiB2 Nanoparticles

Nanoparticles of titanium diboride (TiB2) coated with a conductive polymer and subjected to an oxidizing agent was carried out in this research. TiB2 nanoparticles coated with polypyrrole (PPy) were studied using XRD and TEM techniques. Nitrogen adsorption and desorption properties of nanoparticles are covered with modified polypyrrole to understand better the surface zone, structural features, and pore geometries of the nanoparticles. The water‐based hazardous anionic Congo red (CR) dye was removed using polypyrrole‐coated titanium diboride (PPy@TiB2) nanoparticles. Numerous cutting‐edge experimental techniques, including FTIR, FE‐SEM, EDXS, and element mapping analysis, were used to confirm the CR color’s adhesion to the PPy@TiB2 nanoadsorbent study. While conducting batch experiments, coated TiB2 nanoadsorbents with polypyrrole enhanced the adsorption behaviour. One of the factors evaluated in the adsorption tests was pH; another was contact time, and a third was dose. At pH = 4, 98.75% of Congo red dye was detached using 60 mg of PPy‐coated TiB2 nanoadsorbent. Several sorption‐desorption cycles were performed on this nanoadsorbent to determine its reusability. An excellent adsorption capacity for water treatment is reported in PPy‐coated TiB2 nanoadsorbent.