Microhardness Properties Research Articles

Potential plasma facing materials: A case study on CeB6 particulate reinforced W–1Ni matrix composites produced via different sintering techniques

Tungsten (W) is the most promising material for future plasma-facing materials. Its alloys or composites reinforced with various compounds have been studied to improve the irradiation resistance of W. This study aimed to investigate the effect of boron-containing reinforcement in the W matrix against He+ ion irradiation. Cerium hexaboride (CeB6) particulates, which have high neutron shielding properties, were incorporated into the W matrix pre-alloyed by 1 wt% Ni (W1Ni). CeB6 powders were home-made and prepared from CeO2/Mg/B2O3 powder blends via mechanochemical synthesis and purification steps. 1, 5, and 10 wt% CeB6 powders were added to pre-alloyed W1Ni by mechanical alloying, and then they were consolidated by using pressureless sintering (PS, 1400 °C, 1 h) and spark plasma sintering (SPS, 1410 °C, 1 min) techniques. CeB6 particle-reinforced W1Ni composites contained different amounts of reinforcements were prepared by two different sintering methods and were compared with respect to their compositional, microstructural, and microhardness properties and wear and irradiation behaviors. Based on the results, increasing the CeB6 reinforcement amount in the composite triggered the formation of the W2B phase, especially in the W1Ni–10CeB6 composite after both sintering methods. The mechanical and irradiation properties were enhanced more by increasing the CeB6 amount in the case of using the SPS method. When compared to other sintered samples, the SPS'ed W1Ni–10CeB6 composite has the lowest specific wear rate of ∼4 × 10−7 mm3/Nm and the maximum hardness value of ∼21 GPa. According to surface deformation, the W1Ni–5CeB6 composite exhibited comparatively higher resistance to He+ ion irradiation.

Process Optimization of Spark Plasma Sintered Parameters for Ti-Al-Cr-Nb-Ni-Cu-Co High Entropy Alloy by Response Surface Methodology

In this study, the influence of operating parameters on the relative density and microhardness property of a septenary equiatomic Ti-Al-Cr-Nb-Ni-Cu-Co high entropy alloy developed via spark plasma sintering (SPS) process was investigated at constant heating rate (100 °C/min), dwell time (5 min), pressure (50 MPa). Using response surface methodology (RSM) on the sintering temperature (ST) and milling time (MT) as the process variable parameters, a predictive model was established. The design of experiment approach was employed to minimize numbers of runs of experiment, which invariably eliminates trial by error associated with traditional experimental methods. MT and ST were taken as the variables towards the development of the design model. The optimum operating parameters were predicted using the user-defined design (UDD) under RSM and the result was validated through experiments. Observation from the results shows that MT and ST play a significant role in achieving high densification, which translates to high hardness. At 900 °C ST and MT of 10 hours, the highest hardness value of 580.1 HV, densification of 99.98%, and percentage porosity of 0.02% were recorded.

Effect of Ni element on microstructure and properties of cold-rolled 316 L austenitic stainless steel

In this current investigation, the impact of Nickel (Ni) on the microstructural attributes and properties of a cold-rolled 316 L sheet was examined. The microstructure and phase configuration of austenitic stainless steels, specifically 316 L and 316LNi, were meticulously characterized through the utilization of metallography, X-ray Diffraction (XRD), and Electron Backscatter Diffraction (EBSD) techniques. Subsequent assessments were conducted to evaluate magnetic characteristics, microhardness, and tensile properties. The phase structure of both austenitic stainless steels conforms to a Face-Centered Cubic (FCC) crystal lattice, whereby the grain content oriented along the (110) plane progressively escalates with augmenting degrees of cold rolling. The magnetic conductivity of these austenitic stainless steels satisfactorily adheres to established standards. The incorporation of Nickel (Ni) into the alloy composition enhances the cold deformation capacity of 316 L stainless steel. However, substantial plastic deformation yields heightened dislocation density, thereby promoting enlarged grain dimensions upon solution treatment. Throughout subsequent cold rolling deformation sequences, the augmented grain size observed in 316LNi stainless steel leads to a reduction in dislocation density within the equivalently ordered cold-rolled plate. Simultaneously, this augmented grain size engenders a decline in grain boundary content coupled with an augmentation in twin content. Consequently, the interplay of grain coarsening, diminished dislocation density, and twin-induced softening collectively bestows upon 316LNi stainless steel a lower tensile strength compared to 316 L stainless steel, albeit accompanied by heightened plasticity.

Microstructures and improved properties of Cu–Mo alloys induced by high current pulsed electron beam irradiation

In this paper, a Cu–Mo alloying layer with improved properties was fabricated by high current pulsed electron beam (HCPEB) irradiation. The microstructure of the modified layer was investigated by x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The microhardness and friction properties were also measured. After HCPEB irradiation, nano Mo particles, solid solution, and long-period superlattice structures were generated on the surface of Cu–Mo alloys, together with the formation of defect structures. These microstructures led to a significant increase in the surface hardness. The results of sliding wear tests indicated that the HCPEB-irradiated samples exhibited better properties compared with the initial one, which was attributed to the ultrafine Mo particles and the hardened surface.

Highly-efficient additive manufacturing of Inconel 625 thin wall using hot-wire laser metal deposition: Process optimization, microstructure, and mechanical properties

Hot-wire-based laser metal deposition (HW-LMD) technique was used for additive manufacturing of Inconel 625 thin-walled parts. The desired process window was obtained through the Taguchi experiment design, and the defect-free Inconel 625 thin-walled structures were efficiently manufactured with a wire deposition rate of 1.72 kg/h. The microstructure, phase composition, microhardness, and tensile properties of the Inconel 625 thin walls were studied in detail. The results showed that the microstructure of the Inconel 625 thin wall was mainly composed of a large number of columnar dendrites with an average grains size of 12.5 μm, and the growth direction of the columnar dendrites was perpendicular to the substrate surface. γ-Ni was the base phase of the as-deposited Inconel 625 thin walls and irregularly shaped Laves precipitates were observed in the inter-dendritic region. The microhardness of the Inconel 625 thin wall over the build direction was homogenous and the average microhardness was 258 HV1, which was 35.7 % higher than that of the wrought alloy. The tensile strength of the as-deposited Inconel 625 thin walls exhibited anisotropy according to the relationships between stress loading direction and microstructural texture. The maximum tensile strength and elongation of the as-deposited Inconel 625 thin wall were respectively 825.91 MPa and 55.62 %, which were close to the wrought alloy 625. Meanwhile, through comparative analysis, it was found that the tensile properties of the Inconel 625 samples fabricated in this study were superior to samples produced using conventional arc additive manufacturing methods.

Influence of metalloid element B on the microstructure and performances of novel FeCoNiVB high-entropy amorphous alloys

The influence of metalloid element B content on the microstructure, microhardness, thermal stability and anti-corrosion properties of (Fe1/4Co1/4Ni1/4V1/4)100-xBx (x = 16 ∼ 32 at.%) high-entropy amorphous alloys was studied systematacially. Results showed that the investigated alloy ribbons owned fully glassy nature. The average microhardness and crystallization onset temperature of these glassy ribbons were over 958 HV0.2 and 757 K, respectively. The self-corrosion potentials of samples were −0.541 ∼ −0.484 V and the most positive potential could reach −0.484 V for the Fe20Co20Ni20V20B20 alloy ribbons. Besides, this equiatomic specimen also owned the smallest corrosion current density of 5.87 × 10−6 A/cm2 and the largest polarization resistance of 9635.7 Ω·cm2. The experimental characterization analysis of alloy ribbons’ immersion tests further proved the credibility of measurement results. Therefore, it is indicated that the equiatomic FeCoNiVB high-entropy amorphous alloy possesses the best corrosion resistance in 3.5 wt% NaCl solution among studied samples and this alloy can be also viewed as a potential functional protective material combined with the anti-corrosion performance, wear resistance and thermal stability.

Effect of laser remelting on the microstructure and corrosion behavior of high-velocity arc-sprayed FeNiCrBSiNbW amorphous coating

Fe-based amorphous coating was produced using high-velocity arc-spraying (HVAS), and then laser remelting (LR) technology was used to treat the as-sprayed coatings (ASC) to prepare the laser remelted coatings (LRC). The morphology, phase composition, microhardness, porosity, and corrosion property of the Fe-based amorphous coatings before and after LR were investigated. The outcomes demonstrated that the internal defects of the ASC were eliminated and the porosity was significantly reduced after LR, which was significant in dramatically enhancing corrosion resistance. After the LR procedure, the ASC's free corrosion potential (Ecorr) in 3.5 wt% NaCl solution increased, and the corrosion current density (Icorr) almost reduced by a factor of ten. Therefore, LR helped to strengthen the corrosion characteristics of Fe-based amorphous coating and improve its microstructure.

A study of microstructure and mechanical properties of (CoCrNi)82Al9Ti9 high entropy alloy by electrical-thermal-mechanical coupled rapid post-treatment

In this work, we have creatively used electrical-thermal-mechanical coupled rapid post-treatment to improve the properties of (CoCrNi)82Al9Ti9 high entropy alloy (HEA). The effect of the electrical-thermal-mechanical coupled field on the phase, microstructure, microhardness, fracture toughness, and compression properties of SLM specimens are investigated. The results show that the SLM specimen exhibits face-centered cubic (FCC) and body-centered cubic (BCC) phases and the microstructure is a dendrite structure. The SLM specimens exhibit imperfections, including porosity and cracks, as well as low densification. After electrical-thermal-mechanical coupled rapid post-treatment, the FCC phase decreases while the BCC phase increases in the SLM specimen, and the microstructure changes from dendritic to recrystallized. The created specimens are healed of defects and the densification is increased to 99.6%. It can be attributed to the combination of the electrical (Electron wind) and thermal effects (Joule heat) of pulse current. Electron wind promotes the diffusion of atoms and expansion of the movement of dislocations, providing the material basis for defect healing and recrystallization. Joule heat provides the substance conditions. The (CoCrNi)82Al9Ti9 HEA has a remarkable improvement in strength and ductility.

Effect of Y2O3 addition on the organization and tribological properties of Ni60A/Cr3C2 composite coatings obtained by laser-cladding

This study aims to enhance the surface toughness and overall performance of arc-shaped nail teeth, which are vital components of presowing film-recovery machinery. Laser cladding technology was employed to deposit Ni60A/Cr3C2 composite coatings with the rare-earth oxide Y2O3 onto 60Si2Mn steel surfaces. The effects of different amounts of Y2O3 on the wear resistance of Ni60A/Cr3C2 composite coatings were evaluated. Scanning electron microscopy (SEM), X-ray diffraction, X-ray photoelectron spectroscopy, and 3D morphological analysis were used to investigate the microstructure, microhardness, elemental distribution, and tribological properties of the coatings. The ideal amount of Y2O3 to add to the mixtures to enhance the wear resistance was determined. The results showed that the coating containing 1.5% Y2O3 and Ni60A/Cr3C2 composite powder exhibited superior overall performance. Coatings with different amounts of added Y2O3 exhibited similar phase compositions, mainly consisting of γ-Ni-based, Ni2Si, M7C3 (M = Cr, Mn), and M23C6-strengthened phases. SEM analysis revealed that the coating with 1.5% Y2O3 exhibited excellent metallurgical bonding with the substrate. In addition, the coating exhibited finer grains, increased density, a more uniform distribution of coating elements, and a microhardness of 990 HV. Fewer grooves and smoother abrasions were observed after the wear test. The wear amount and depth were 14 × 10−4 g and 8.97 μm, which were 22.2% and 55.4% lower than the coating without added Y2O3, respectively. The tribological behavior indicated that adding the appropriate amount of Y2O3 facilitated the grain boundary consolidation while enhancing the adhesive properties of the oxide film, thereby increasing the wear resistance of the coating.

Microstructure, microhardness and mechanical behavior of dissimilar AA7075/AA6061 alloys under friction stir welding

Friction stir welding (FSW) of dissimilar AA6061 and AA7075 aluminum alloys faces challenges such as an unclear forming mechanism and low welding efficiency. In order to improve welding efficiency and elucidate the variations in metallography, Microhardness, and mechanical properties of dissimilar alloy FSW joints, this article designed FSW experiments using the Taguchi method with welding speeds ranging from 600 to 1000 mm/min. We studied the relationship between material mixing and welding defects through macroscopic metallography, microscopic metallography, and Microhardness, while the impact of welding parameters on the microstructure and properties was evaluated. The results show that void defects do not exist in dissimilar alloy FSW joints, and the Microhardness changes are “U” and “W” shaped. Material mixing played a decisive role in determining the microstructure and properties of dissimilar aluminum alloy FSW joints, with increased rotational speed enhancing material flow. The order of influence on the mechanical properties of the joint was found to be plunge depth, welding speed, and rotational speed. Under the conditions of 1000 mm/min, 2400 rpm, and 0.25 mm, the yield strength (YS) and ultimate tensile strength (UTS) of the dissimilar alloy FSW joints reached 87.3% and 73.4% of the AA6061-T6 alloy, respectively.

Microstructural, microhardness and electrochemical properties of heat-treated LENS in-situ synthesized Ti–Al-x(Mo, Si) alloys

So as to explore the opportunity of property enhancement of TiAl-based alloys, studies of microstructural evolution after processing with heat treatments are to be expected. Therefore, the objective of this present study is to investigate how additions of silicon (Si) and molybdenum (Mo) as alloying elements affects the microstructure, microhardness, corrosion behaviour, and wear properties of Ti–Al-x(Mo, Si) alloys made from constituent elemental powders through in-situ alloying laser engineered net shaping (LENS) technique. The influence of the feed rate of Si powder (0.1 rpm, 0.2 rpm and 0.3 rpm) on Ti–Al-xMo was studied at 0.1 rpm and 0.2 rpm Mo feed rate, respectively. Heat treatment at 1200 °C for 15, 30, and 60 min was performed after LENS in-situ alloying, and furnace cooling (FC) was the final step. The microstructure of the produced alloys was analyzed via Scanning electron microscopy (SEM) fitted with energy dispersive spectroscopy (EDS). Using a tribometer and a potentiodynamic polarization test, the alloys' wear characteristics and corrosion behaviour were studied. Based on the results, it was noticed that microhardness values decrease after heat treatment for all the samples produced. Owing to the combined effects of Mo and Si, both the βo-TiAl and ζ-Ti5Si3 phases lead to solid precipitation hardening and solution strengthening at the grain boundaries. The XRD analysis confirmed γ, α2, α, βo and ζ-Ti5Si3 phases occurrence in the as-built alloys. The LENS fabricated alloys demonstrated improved wear properties and marginally change in corrosion behavior after heat treatment.

Microstructure and properties of aluminium matrix hybrid nanocomposite

ABSTRACT Aluminium metal matrix nanocomposites (MMNCs) reinforced with particulate have been in the limelight recently due to their improved tribological and mechanical properties such as stiffness, strength, impact resistance, wear resistance, etc. It is well known that carbon nanotube and silicon carbide nanomaterials are widely used as reinforcements in various types of metal or alloy matrix materials. However, hybrid metal matrix nanocomposites reinforced with more than one type nanomaterials are rarely reported in the literature. In this work, a novel aluminium matrix hybrid nanocomposite with carbon nanotube and nano SiC has been fabricated. Properties of hybrid nanocomposites are compared with nanocomposites reinforced with individual reinforcements. Vicker’s micro-hardness property of specimens was tested at 100 gmf load applied at 10 s dwell time. The hardness and compressive strength have increased 111% and 58%, respectively with the reinforcement of nanoparticles in the metal matrix. Dry wear property of specimens was carried out at 35, 40 and 45 N load with variable speeds viz. 500, 550 and 600 rpm. Wear resistance increases as the carbon reinforcement increases in the metal matrix. The wear mechanism of nanocomposite materials has been evaluated by using scanning electron microscopic analysis.

Tensile properties and microstructural evolution of 17–4 PH stainless steel fabricated by laser hybrid additive manufacturing technology

Wire-based laser directed energy deposition (LDED) technology is an attractive and efficient additive manufacturing technology, which shows great potential in the process of manufacturing high-value engineering components. However, the thermal effect will lead to a large amount of residual tensile stress in the components, and the large crystal structures after solidification seriously affects the tensile performance. The pursuit of high mechanical properties in additive manufacturing components have prompted researchers to seek new strengthening process to produce high-strength components. Therefore, in this paper, laser shock peening (LSP) composite wire-based LDED were used for the additive manufacturing of 17–4 PH stainless steel under the specified experimental conditions, and the effects of LSP on microstructure evolution, microhardness, and tensile properties of wire-based LDED components were systematically studied. Results showed that uniform grains with an average size of 2.31 μm were generated on the top surface of specimen due to the ultra-high plastic strain induced by LSP shock wave. The size of hierarchical martensitic units shows varying degrees of reduction after LSP treatment, which is shown by the width decrease of packet, block and lath. Dynamic recrystallization caused by rearrangement and annihilation of high-density dislocations promoted the grain refinement. Meanwhile, the residual stress was completely converted from tensile state into compressive state with a maximum value of 425 MPa, and the microhardness was also enhanced to a peak value of 432 HV. In addition, we observed that the high-density dislocation environment created by LSP treatment promoted the further precipitation, and the aggregation phenomenon of precipitates was observed in the dense dislocation area. Furthermore, the tensile strength and elongation of LSP treated specimen were improved significantly, which was attributed to the combined effects of grain refinement, introduction of dislocation structures, precipitation strengthening and gradient residual compressive stress. In summary, laser hybrid additive manufacturing technology provides a new idea and method for the production of high-performance precipitation hardening stainless steel components.

The influences of vanadium addition and temperature on the microstructure, and mechanical properties of Al0.1CoCrFeNiVx multi-principal element alloys

The study aimed to examine the crystal structure, microstructure, microhardness, and tensile properties of Al0.1CoCrFeNiVx (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) multi-principal element alloys. Both Al0.1CoCrFeNi and Al0.1CoCrFeNiV0.2 alloys were single FCC phase solid solutions. σ-phase precipitated in Al0.1CoCrFeNiV0.4 alloy. The volume fraction of σ-phase increased as V content increased from x = 0.4 to 1.0. The volume fraction of σ-phase in Al0.1CoCrFeNiV alloy was found to be 48.4 vol%. It was shown that to predict the phase composition of multi-principal element alloys containing σ-phase employing solid solution formation model, coupling it with criteria of σ-phase formation was necessary. Moreover, when the V content was x ≤ 0.4, the alloys showed good toughness and ductility (> 49%). However, a continuous increase in V content led to a higher volume fraction of σ-phase, which enhanced the strengthening/hardening effect until reaching the embrittlement threshold. At x = 0.4, the alloy exhibited a better balance between strength and plasticity. Uniaxial tensile tests were performed on the annealed Al0.1CoCrFeNiV0.4 alloy at different temperatures. Results suggested that the alloy retains excellent plasticity (> 45%) at 500 ℃. Nevertheless, it exhibited a decrease in strength and plasticity with elevated temperatures. The addition of V caused a significant increase in ultimate strength and elongation at mid-temperatures (500–700 ℃) compared to Al0.1CoCrFeNi alloy. The engineering stress-strain curves of the Al0.1CoCrFeNiV0.4 alloy displayed serrated flow at temperatures from 300 ℃ to 700 ℃. The serration type transitioned from A-type to C-type as the temperature rose.

Investigation of Microstructure, Microhardness and Thermal Properties of Ag-In Intermetallic Alloys Prepared by Vacuum Arc Meltings

Investigation of Microstructure, Microhardness and Thermal Properties of Ag-In Intermetallic Alloys Prepared by Vacuum Arc Meltings

Microstructure and mechanical properties of Flexible Ring Mode laser welded 304 stainless steel

Flexible Ring Mode (FRM) laser welding is a relatively new composite laser welding technology. The present study focused on the FRM laser welded joints produced from 4.5 mm-thick 304 stainless steel. The effects of various laser modes on the macroscopic morphology, microstructure, microhardness, and tensile properties of the produced welded joints were systematically investigated. The results showed that, when the ring laser power was set at 1000 W and the center laser power at 3000 W, a maximum weld area of 6.23 mm2 was obtained. Employing a composite laser with a center laser power greater than the ring laser power resulted in the fewest number of welding spatter particles on both sides of the weld bead, indicating an effective inhibition of welding spatter by the ring laser. Conversely, using a composite laser with a center laser power equal to the ring laser power still led to the presence of small welding spatter particles, indicating differences in the laser combination modes in suppressing welding spatter for the welding of 304 stainless steel. Increased cooling and a large presence of small turbulence contributed to the grain refinement in the fusion zone of the welded joints produced using a composite laser with a central laser power greater than the ring laser power. Consequently, this welded joint exhibited the highest maximum tensile strength among all tensile test specimens reaching 95.2 % of the base metal’s maximum tensile strength. However, the fractured surfaces of the tensile test specimens produced using a composite laser with a center laser power equal to the ring laser power exhibited the highest number density and largest size of oxide particles, resulting in a joint elongation of only 77.3 % of the base metal’s elongation. This study emphasizes the potential application of this FRM laser and provides theoretical guidance for selecting the optimal laser combination mode for FRM laser welding of stainless steel.

Influences of laser remelting on mechanical performances of AISI4140 steel

Laser remelting is a promising in-operando method to improve surface quality and eliminate defects simultaneously in the laser-powder bed fusion process. In this study, the optimal processing parameters for laser remelting and the influences of laser remelting on porosity, microcracks, surface roughness, microhardness and mechanical properties of the AISI 4140 steel manufactured by laser-powder bed fusion were investigated. The results showed that laser remelting improved the relative density to 99.6% and defects in the microstructure changed from lack of fusion to keyhole morphology as the number of remelting steps increased. The roughness on the upper surface was reduced by 73% after remelting, but the roughness on the lateral surfaces deteriorated by 4.5% when remelting twice. Specimens built in the transverse orientation and treated with a single remelting step exhibit the highest tensile strength (1277 MPa). Furthermore, there is a slight improvement in the fatigue limit after remelting once. However, laser remelting in the manufacturing process did not eliminate microcracks.

Microstructural evolution and anti-corrosion properties of laser cladded Ti based coating on Q235 steel

Titanium (Ti) based coatings laser cladded on steels could effectively protect steels from corrosion in the marine environment. However, the microstructural evolution and underlying solidification mechanisms for Ti based coatings laser cladded on steels are still unclear due to the nonequilibrium solidification processes during laser cladding. In this study, a Ti based coating was prepared on a Q235 steel by laser cladding. The microstructural evolution and corrosion properties of the coating were systematically investigated by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), electron probe micro-analysis (EPMA) and electrochemical measurements in 3.5 wt% NaCl solution. Four typical regions form in the Ti based coating and the constituent phases evolve from α-Fe + TiFe2 phases to TiFe2 phase, then to TiFe phase, and finally to Fe0.2Ti0.8 (metastable β-Ti) + TiFe + Ti2Fe phases from the fusion interface to the coating surface. Temperature gradients and solidification rates determine the microstructure morphologies of the Ti based coating, and the contents of Fe in the Ti based coating evolve and affect the phase transformations at different distances from the fusion interface. Moreover, the Ti based coating shows better anti-corrosion properties than the substrate. The effect of micro-strain at different regions on the microhardness and corrosion properties is also discussed. This study can be the base of optimizing the microstructure of laser cladded Ti based coatings on steels for better corrosion performances.

Electrochemical and Tribological Performance of Ti–Al with xNb Addition Synthesized via Laser In situ Alloying

Additive manufacturing is a growing technique of producing 3D parts directly using metal powders or wires melted with a high-powered intensity beam or laser. It is still a challenging process as to how laser processing parameters such as gas flow rate and powder flow rate can profitably be adopted to significantly produce Ti–Al-based materials from elemental powders to synthesize alloys that are defect-free and have good mechanical properties. The density of titanium aluminide (Ti–Al) intermetallic alloys makes it gain lots of interests due to its potential ability to substitute nickel-based superalloys in gas turbine engines. This work aims to investigate the effects of Niobium (Nb) additions on Ti–Al–xNb ternary alloys created via the use of 3D printing technology, specifically looking at microstructural evolution, microhardness, electrochemical behavior, and tribological properties. Ti–Al–Nb alloy was synthesized at scan speed of 26 in/min and laser power of 450 W. The structural morphology of the alloys produced was investigated using scanning electron microscopy equipped with energy dispersive spectroscopy and the electrochemical studies of the in situ alloyed Ti–Al–xNb were studied using potentiodynamic techniques. Using an Emco microhardness tester, the microhardness characteristics of the produced TiAl–xNb alloys were examined. From the results obtained, it was observed that the microstructure showed not much substantial cracking or crack initiation. The micrographs are evident of refined microstructure associated to increase in Nb feed rate with α-Ti3Al, γ-TiAl and precipitates of β-TiAl phases as the distinctively identified in the microstructure. The highest recorded microhardness value of 679.1 HV0.5 was achieved at Nb feed of 0.5 rpm and gas carrier of 2 L/min. The fabricated Ti–Al–Nb alloys showed good corrosion resistance behavior in HCl and appreciable wear characteristics with coefficient of friction of 0.412, 0.401, and 0.414 µ at B1, B3, and B5, respectively.

Study the effects of TiB2 reinforcement on the AA-2014 matrix fabricated by friction stir processing

This study explores the impact of TiB2 nanoparticles on the microstructure, microhardness, and tensile properties of AA-2014 surface composite manufactured through Friction Stir Processing (FSP). A series of experiments were conducted with varying FSP parameters, and the findings were compared with the base metal. Microstructure studies revealed optimal bonding between TiB2 and the AA-2014 substrate at 1200 rpm, surpassing results from 900 and 1600 rpm. However, microstructural analysis unveiled agglomeration of particles and void formation on the composite surface. Microhardness values indicated a substantial increase from 88 HV (AA-2014) to 138 HV (AA-2014/3%TiB2 @1200rpm), attributed to the presence of TiB2 nanoparticles and FSP-induced modifications. Ultimate Tensile Strength (UTS) values exhibited a noteworthy improvement from 290 MPa (AA-2014) to 465 MPa (AA-2014/3%TiB2 @1200rpm), emphasizing the positive influence of uniform TiB2 dispersion achieved during FSP. The study underscores the effectiveness of TiB2 reinforcement and FSP in enhancing the mechanical properties of AA-2014 surface composite, despite observed microstructural features.