Thickness Of Intermetallic Layer Research Articles

Effects of annealing temperature on the interfacial microstructure and bonding strength of Cu/Al clad sheets produced by twin-roll casting and rolling

Abstract In this paper, Cu/Al clad sheets were prepared by twin-roll casting and multi-pass cold rolling. Annealing treatment was performed at temperatures of 250 °C, 300 °C, 350 °C and 400 °C, separately. The influences of the annealing temperature on the interface layer structure, peel strength and peeled surface microstructure of the clad sheets were studied. The crack propagation behavior in the peeling process of the clad sheets was revealed, and the strengthening mechanism of the interface was explained. The results showed that the Cu/Al interface metallurgical bonding rate increased and the intermetallic compound layer thickness could be controlled within 550 nm after annealing at 250 °C, which encouraged more cracks to propagate along the Al matrix, and the average peel strength could reach approximately 39 N/mm. However, after high-temperature annealing treatment (350 °C and 400 °C), the clad sheet broke completely in the intermetallic compound layer, and a large number of cleavage fractures appeared, which caused the bonding strength to decrease sharply.

Evaluation of capabilities of ultrasonic vibration on the surface, electrical and mechanical behaviours of aluminium to copper dissimilar friction stir welds

Placement of the base materials in friction stir welding of aluminium to copper remains a significant aspect that influences the complete weld formation. Aluminium and copper were joined in different types of base material positions by friction stir welding and ultrasonic vibration-assisted friction stir welding. It was found that the roughness of the weld surfaces is reduced with the addition of ultrasonic energy during the welding, mainly in the type I joints. Besides, the aluminium/copper joint strength increased with a decrease in the intermetallic compounds layer thickness and sizes of the distributed copper particles in the type I and type II joints, respectively. The improvement of the strength seemed higher when copper was placed at the retreating side due to the aspect of mixing mechanisms between aluminium and copper in the stir zone, which established aspects of distributed copper particles. The digital image correlation technique was employed to investigate the major principal strain distribution along the cross-section of the welds as well as fracture step processes (strain evolution, crack inception, and dissemination) of friction stir welding and ultrasonic vibration-assisted friction stir welding joints. Welds performed with ultrasonic energy did not experience any form of improvement of the electrical conductivity. Nevertheless, the electrical conductivities of the friction stir welding and ultrasonic vibration-assisted friction stir welding joints are found to be within the range of the electrical conductivities of the base materials.

Modelling of intermetallic layers formation during solid-liquid joining of dissimilar metallic materials

Joining of dissimilar metallic materials gives rise to the production of components with improved properties. At the joint interface, the formation of brittle intermetallic layers might deteriorate the component application. Therefore, its formation and growth must be well understood and carefully controlled. Numerical simulations assist in the determination of processes parameters to obtain the desired bond characteristics. In solid-liquid joining processes, the melt movement plays an important role und must be accounted in the simulations. In this paper, a mathematical model at the continuum scale is used for the description of the interface formation during solid-liquid joining. The description of convection and advection of the molten alloy and the dissolution of the solid substrate are of interest. The substrate dissolution into the melt alters the local composition of the molten alloy, leading to precipitation of intermetallic compounds on the substrate surface during the solidification process. To account for these phenomena, convection heat transfer with phase transformation and diffusion and reaction at the solid-liquid interface are considered in the mathematical model that is based on conservation equations of mass, momentum, energy and species. The different scale problem is solved by applying a dynamic mesh refinement at the interface to accurately solve the intermetallic layer growth. The model was implemented in OpenFoam® and simulation results for the intermetallic layer thickness as a function of solid substrate temperature (Ts) for compound casting between initially liquid Al and a solid Cu substrate are presented. In general, for Ts initial value ranging from 400 to 700 °C while keeping the initial Al melt temperate at 750 °C, the intermetallic layers thickness increases as Ts increases.

High cycle fatigue performance of cold metal transfer (CMT) brazed C-Mn-440 steel joints

In this work, C-Mn-440 steel was joined using CMT brazing with CuAl8 filler. Results showed that wettability, fraction of intermetallic phases in bead and intermetallic layer at the interface of bead-steel contributed to the shear-tensile strength of the joints whereas fatigue strength was most influenced by the wetting ability (wetting length and wetting/toe angle) of filler due to higher stress accumulation at the root and toe. Joints brazed in pull mode exhibited higher shear-tensile and fatigue strength in comparison to 0° and push mode which can be attributed to improved wetting ability, thicker intermetallic layer and higher dispersive phase fraction.

Effect of Mo Nanoparticles on the Growth Behavior of the Intermetallic Compounds Layer in Sn3.0Ag0.5Cu/Cu Solder Joints.

The reliability of solder joints, which is affected largely by the interfacial intermetallic compounds layer, is of great importance to the performance of electronic devices. In this paper, a novel composite solder with Mo nanoparticles doped in Sn3.0Ag0.5Cu solder was prepared. Solder/Cu joints were prepared using Sn3.0Ag0.5Cu solder or Mo nanoparticles reinforced solder with Cu substrates. The effect of the nanoparticles on the growth of intermetallic compounds during isothermal aging was investigated. It was found that the addition of Mo nanoparticle markedly suppressed the increase in thickness of the interfacial intermetallic compounds layer during isothermal aging. The atomic diffusion coefficients during isothermal aging in Sn3.0Ag0.5Cu solder and in the novel doped solder were determined experimentally. Mo nanoparticles were found to decrease the diffusion coefficient in the composite solder. The high specific surface area of the nanoparticles makes them easily adsorbed and hinders the diffusion of Sn and Cu atoms. This is consistent with an increase in the diffusion activation energy due to the addition of Mo nanoparticles in Sn3.0Ag0.5Cu solder.

Studies on the characterization and morphological features of the coating on interstitial free steel dipped in molten Al-Si-Mg alloy at 800 °C

Interstitial-free (IF) steel specimens were coated by hot-dip aluminizing process bearing bath composition as Al-6.9% Si-1.4% Mg and bath temperature at 800°C. Dipping time varied for 0.5, 1, 3 and 6min. The objective of the present study is to conduct a systematic investigation to identify and analyse the formation of various phases and compounds in the coating. Studies on aluminizing of steel had indicated the presence of an intermetallic layer adjacent to steel substrate. In this study, the morphological features obtained after hot dipping at 800°C were investigated. For the application of aluminized steel sheets in industry for manufacture of tubes and pipes, the adherence of the aluminized coating must be ensured. This property of the coating is influenced by the morphological features of the coating. Aluminizing being thought of a possible substitution of galvanizing owing to its promise to evolve lesser volume fraction of intermetallic phases and consequently known to generate a ductile coating. The entire coating consists of an outer Al-Si topcoat and a thin intermetallic layer which composed of an outer θ-FeAl3 and inner η-Fe2Al5 layers. The thickness of intermetallic layers was found to increase with the increase of dipping time in a near parabolic manner.The phases formed on the IF steel substrates were characterized by scanning electron microscopy with EDS, X-ray diffraction, EPMA and EBSD techniques.Interesting findings from XRD include the presence of Al3FeSi2 (τ4) and Al2FeSi (τ3) phases, which normally appear after annealing of aluminised sheet. A distinct elemental Si peak was found in XRD study. Presence of Mg in the form of Mg2Si was also found in XRD and supported by EPMA investigation. Presence of several ternary Al-Fe-Si (τ3, τ4, τ5) and binary FeAl3 and Fe2Al5intermetallic phases were identified by composition profile analysis from SEM based EDS and GDOES and further confirmed by EBSD. Presence of Si humps in the top and intermetallic layer attributed by the presence of Si-bearing phases or elemental pro-eutectic Si in Al-Si alloy were also indicated in SEM-EDS and GDOES study. Variation of surface topographical features of the HDA steel substrates with increasing dipping durations were examined and reported for the first time by using AFM. Formability tests were conducted by bending the samples 180° over a mandrel. None of the specimens showed any tendency of flaking exhibiting excellent bonding of the coating with IF steel substrate.

Nanocomposite SAC solders: the effect of adding CoPd nanoparticles on the morphology and the shear strength of the Sn–3.0Ag–0.5Cu/Cu solder joints

The effect of bimetallic monodisperse CoPd nanoparticles on the microstructure and the shear strength of the Cu/ SAC305/Cu solder joint was investigated. The nanocomposite Sn–3.0Ag–0.5Cu (SAC305) solders with 0.1, 0.3, 0.5, and 1.0 wt% nanoCoPd were prepared through a paste mixing method. The employed bimetallic nanoparticles were produced via a modified oleylamine method. The microstructural analysis of as-solidified Cu/solder/Cu joints was performed by scanning electron microscopy. The results showed that initial additions of CoPd nanoparticles into the SAC305 solder promoted the growth of the interfacial planar-type Cu3Sn IMC layer; while the average thickness of the interfacial scallop-type Cu6Sn5 IMC layer slightly decreased. Further additions of the nanosized CoPd admixtures to the SAC305 solder paste lead to a significant increase of the average thickness of the Cu6Sn5 intermetallic compound layer up to 40%. The shear strength measurements were performed to investigate a relationship between the microstructure and mechanical properties of the investigated solder joints. The results indicated a decrease in the shear strength of the SAC305 solder joint by addition of 0.1 wt% CoPd NPs, while a difference in absolute values between solder joints with 0.3, 0.5, and 1.0 wt% nanoCoPd was practically insignificant.

Pt–Ti Alloy Coatings Deposited by DC Magnetron Sputtering: A Potential Current Collector at High Temperature

Metallic platinum–titanium coatings were deposited by co-sputtering of two metallic Pt and Ti targets in pure argon atmosphere. The titanium concentrations varied from 0 to 47 atomic percent and were adjusted as a function of the current applied to the titanium target. The structural and chemical features of these films were assessed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). All as-deposited coatings exhibit a perfect covering of the alumina pellets’ substrate surface. The coatings containing more than 4 at.% Ti are amorphous, whereas the others crystallize in the face-centered cubic (fcc) structure of platinum. After an annealing treatment under air for 2 h, all of the coatings adopt the fcc structure with a crystallization temperature depending on the titanium content. For titanium concentrations higher than 32 at.%, the TiO2 phase appears during the annealing treatment. For the smaller film thickness of Pt–Ti alloys (15 nm), the Ostwald ripening mechanism is observed by SEM increasing the annealing temperature regardless of the content of Ti. The film resistivity measured at room temperature is lower than 7 × 10−4 Ω·cm and increases with the temperature to achieve an insulating behavior (in air and reducing atmosphere Ar-H2 (90-10) at 1123 K the resistivity is ρ ≈ 10+36 Ω·cm). When the thickness of intermetallic Pt3Ti layer is higher than 50 nm, the coating is continuous and the resistivity is below 5 × 10−4 Ω·cm in air and in reducing atmosphere (Ar with 10% of H2) up to 1273 K.

A Study on Corrosion Resistance and Mechanical Performance of 6061 Aluminium Alloy: Galvanized Mild Steel Electron Beam Welds at Varying Welding Parameters

Dissimilar welds of steel and aluminium alloys have an inherent problem of the vast difference in solid solubility which questions their integrity. The present study elaborates on the mechanical failure and corrosion degradation of 6061 Al—galvanized mild steel lap joints fabricated by electron beam welding as a function of varying parameters such as processing speed, voltage and current. The interfaces of two weld specimens were examined using scanning electron microscopy, phase analysis by micro-area X-ray diffraction and hardness testing by Vickers micro-hardness tester. Results showed the generation of the intermetallic layer at the weld seam–mild steel interface in the specimens. The composition of the Al–Fe intermetallics in the layer was confirmed by micro-XRD analysis. The layer width increased with increased heat input and average width varied between 11 and 16 µm in the specimens. The micro-hardness of the layer was found to increase with a decrease in processing speed during welding. The corrosion resistance and mechanical strength of welds were evaluated as per ASTM G 67-04 and D 1002, respectively. The microstructures at weld interfaces have shown intergranular corrosion after nitric acid exposure for 24 h according to ASTM G 67-04. Weight loss analysis was done after the corrosion test. It was identified that welds fabricated at higher voltage exhibited greater weight loss of 55.9 mg and specimen joined at lower voltage was found to exhibit a weight loss of 41.1 mg, respectively. High intermetallic layer thickness in the welds resulted in failure at the weld seam region during lap shear testing.

Suppression of intermetallic reaction layer by ultrasonic assistance during friction stir welding of Al and Mg based alloys

This article aims to discover the effects of ultrasonic vibration during friction stir butt welding of AA6061-T6 and AZ31B Mg alloys. In the present attempt, the ultrasonic vibrations are enforced along the welding direction via novel horn attachments and welding tool. The experimental outcomes result in a significant improvement in weldment mechanical properties (ultimate tensile strength 22.1%, and weld efficiency 22.0%) with ultrasonic assistance. A major reduction in intermetallic layer thickness is also obtained across the dissimilar interfaces treated with ultrasonic vibrations. The correlation analysis evidence that at the parameters, where the ultrasonic joints exhibit maximum improvement in weld strength, the intermetallic layer thickness shows a maximum reduction. The energy dispersive X-ray spectrometry analysis of the weld interface confirms the formation of intermetallic phases βAl3Mg2 and γAl12Mg17 whose thicknesses are reduced across the acoustic regions. Furthermore, a significant improvement in interfacial bonding, enhanced material mixing and subsequent diminution in weldment anomalies have been found in the joints made with ultrasonic assistance.

Effect of flux functional group for solder paste formulation towards soldering quality of SAC305/CNT/Cu

PurposeThe purpose of this paper is to investigate the wettability and intermetallic (IMC) layer formation of Sn-3.0Ag-0.5Cu (SAC305)/CNT/Cu solder joint according to the formulation of solder paste because of different types of fluxes.Design/methodology/approachSolder pastes were prepared by mixing SAC305 solder powder with different flux and different wt.% of carbon nanotube (CNT). Fourier transform infrared spectroscopy was used to identify functional groups from different fluxes of as-formulated solder paste. The solder pastes were then subjected to stencil printing and reflow process. Solderability was investigated via contact angle analysis and the thickness of cross-sectionally intermetallic layer.FindingsIt was found that different functional groups from different fluxes showed different physical behaviour, indicated by contact angle value and IMC layer thickness. “Aromatic contain” functional group lowering the contact angle while non-aromatic contain functional group lowering the thickness of IMC layer. The higher the CNT wt.%, the lower the contact angle and IMC layer thickness, regardless of different fluxes. Relationship between contact angle and IMC layer thickness is found to have distinguished region because of different fluxes. Thus it may be used as guidance in flux selection for solder paste formulation.Research limitations/implicationsHowever, detail composition of the fluxes was not further explored for the scope of this paper.Originality/valueThe quality of solder joint of SAC305/CNT/Cu system, as indicated by contact angle and the thickness of IMC layer formation, depends on existence of functional group of the fluxes.

In-situ investigation of crack initiation and propagation in roll-bonded five-ply ASS/Al/Mg/Al/ASS laminated composites during tensile test

In this study, 304 austenitic stainless steel (ASS)– 1060 aluminum alloy (Al)– AZ31 magnesium alloy (Mg) five-ply laminated metal composites (LMCs) ASS/Al/Mg/Al/ASS were prepared by hot rolling and subjected to annealing at different temperatures. Both the lamellar interface between Mg-layer and Al-layer (Mg/Al) and the interface between Al-layer and ASS-layer (Al/ASS) bonded well, and no new phases were observed at the lamellar interfaces after hot rolling. However, intermetallic layers of Mg17Al12 and Al3Mg2 would form at the lamellar interface Mg/Al when laminated composites were annealed at 300 °C or above temperature. The mechanical properties of LMCs could be significantly improved by annealing at 200 °C for 1 h. With the annealing temperature further increasing up to 300 °C or more, however, both the tensile strength and the uniform plastic elongation decreased due to the presence of intermetallic layers and their premature rupture. For the LMCs in the rolled state or annealed at 200 °C, the tensile curves exhibited a two-step fracture; while for the LMCs annealed at 300 °C or 400 °C, the tensile curves presented a three-step fracture. In-situ tensile test showed that the fracture processes of the LMCs without intermetallic layers included necking, crack initiation at the interfaces Al/Mg and their partial delamination, crack propagation into Mg-layer along 45° angle, fracture of the Mg-layer and finally of the Al-layer and ASS-layer. The obvious necking of the LMCs before cracking and interlaminar delamination indicated a strong combination between the layers. However, no necking was observed before delamination but a premature failure of intermetallic layer occurred in the LMCs annealed at temperature of 300 °C or above. For the LMCs annealed at 300 °C, cracks first initiated and propagated along the intermetallic layer; while for the LMCs annealed at 400 °C, cracks first generated in crosswise in the thick intermetallic layer which then fractured into segments, resulting in an early delamination and fracture of Mg-layer.

Intermetallics formation during hot dip galvanizing of high carbon steel

From the moment of immersion, the reaction between molten zinc and solid steel starts forming intermetallic phases. This diffusion-controlled process is largely responsible for the final phase composition of zinc coatings. Several literature sources describe this phenomenon for interstitial free steels, but high-carbon steels are rarely being used as substrates. Therefore, in this work high-carbon steel substrates were used. Multiple samples were created by hot-dipping at various immersion temperatures ranging from 450 to 490 °C and times from 24 to 60 s to investigate mainly the morphology of the obtained intermetallic phase layers. Investigation was carried out mainly by SEM on 20 condition, where several hundred sites were investigated in total to achieve statistically relevant information. It was found that while increasing the immersion time influences mainly the thickness of individual intermetallic phase layers, the temperature influenced mainly their morphology. It was also observed that these results are significantly different compared to ones found in literature for interstitial free steels.

Effect of nickel on formation of transition layer during liquid-phase aluminizing of titanium

Titanium—aluminum, titanium—foam aluminum composites and bimetals obtained by liquid-phase methods, are increasingly used in industry. At the liquid-phase methods as result of the reaction diffusion of titanium and aluminum is formed transitional intermetallic layer at the phase boundary of the composite, which reduces the mechanical properties of titanium and composite. To reduce the growth rate of the intermetallic layer between the layers of the composite and increase its mechanical properties, it is proposed to alloy aluminum melt with nickel. The studies of the interaction of titanium and molten aluminum alloyed with nickel made it possible to establish the effect of temperature and aluminizing time on the thickness, chemical and phase compositions of the transition intermetallic layer. The tests showed the effect of the temperature of the aluminum melt, the nickel concentration on the strength properties of titanium—aluminum bimetal.

The Growth of Interfacial IMC Layer in SAC0307 Solder Joints with Specific Grain Orientation Under Electrical and Thermal Coupling Fields

We reported the reliability of Sn0.3Ag0.7Cu (SAC0307) solder joints under electrical and thermal coupling fields, where the c-axes of Sn grains were all nearly parallel to the direction of current and thermal flows. In these studies, individual electromigration (EM), individual thermomigration (TM), and thermoelectric coupling migration behaviors were investigated by applying a current density of 104 A/cm2, and a temperature gradient of 103°C/cm at Cu/SAC0307/Cu solder joints, respectively. The SEM and EBSD were utilized to characterize the morphologies and crystal orientations of each solder joint. The results indicated that the Cu atoms tended to migrate to the anode side under EM. The thickness of an interfacial intermetallic (IMC) layer at the anode increased 3.93 μm. In addition, the Cu atoms diffused toward the lower temperature side under TM, and the thickness of the IMC layer at cold side increased 1.72 μm. When the solder joints were experiencing the coupling fields with the same directions of current and thermal flows, the thickness of IMC layer at anode side (cold side) could increase up to 7.67 μm. The results showed that the effect of thermal flow could assist to accumulate the IMC at the anode side, and accelerate the migration of Cu atoms. This research could help to further understand the reliability behaviors of SAC0307 solders under the service environment.

Friction stir welding of dissimilar metal joints

AbstractFriction stir welding is a solid‐state welding technology, which is suitable for joining dissimilar metals such as aluminium and copper. Because the solidus temperature is typically not exceeded, the formation of intermetallic phases can be reduced when compared to fusion welding processes. In friction stir welding, the intermetallic layer thickness, which determines the seam properties, is influenced by the welding temperature and is formed in correspondence with the Arrhenius law. It is typically in the range of a few hundred nanometers thick. In turn, the process temperature is determined by the process parameters, primarily the rotational speed and the feed rate of the machine tool. In this study, a temperature‐controlled friction stir welding process has been applied to lap joints of aluminium and copper. Welding experiments with various welding speeds and probe lengths were performed in order to assess the effect of the temperature‐time profile near the welding interface. The joints were investigated by tensile shear tests as well as optical microscopy and scanning electron microscopy.

Application of the hybrid process ultrasound enhanced friction stir welding on dissimilar aluminum/dual‐phase steel and aluminum/magnesium joints

AbstractFriction stir welding as a solid‐state joining method with its comparatively low process temperatures is suitable for joining dissimilar materials like aluminum/magnesium or aluminum/steel. Such hybrid joints are of great interest regarding lightweight efforts in different industrial fields like the transportation area. The present work investigates the influence of additionally transmitted power ultrasound during the friction stir welding on the joint properties of EN AC‐48000/AZ91 and EN AW‐6061/DP600. Therefore, conventional friction stir welding was continuously compared to ultrasound enhanced friction stir welding. Light microscopic analysis and nondestructive testing of the joints using x‐ray and high frequency ultrasound show different morphologies of the nugget for the aluminum/magnesium joints as well as differences in the amount and size of steel particles in the nugget of aluminum/steel joints. Scanning electron microcopy proves differences in the thickness of continuous intermetallic layers for the aluminum/steel joints realized with and without power ultrasound. Regarding the tensile strength of the joints the power ultrasound leads to increased joint strengths for EN AC‐48000/AZ91 joints compared to a decrease for EN AW‐6061/DP600 joints. Corrosion investigations show an influence of the ultrasound power on the corrosion properties of EN AC‐48000/AZ91 joints which is attributed to a changed aluminum content in the nugget region. Because of the great potential difference between the magnesium and the nugget phase the transitional area exhibits strong galvanic corrosion. For EN AW‐6061/DP600 joints an increased corrosion caused by galvanic effects is not expected as the potentials of the EN AW‐6061 aluminum alloy and DP600 steel are very similar.

Fabrication of Novel Geopolymer Reinforced Tin Copper Solder in Suppressing Intermetallic Layer Growth

Currently, lead-free composite solder technology system is the new approach that have been considered as a promising replacement for toxic SnPb solder alloy. Sn-0.7Cu was used as matrix solder alloy while fly ash geopolymer and kaolin geopolymer with different compositions (0.5 wt.%, 1.0 wt.%, and 1.5 wt.%) was added as a reinforcement to increase the properties of solder alloy. The solder composite was prepared by using powder metallurgy method which consist of mixing, compaction, and sintering process via microwave oven. Microwave sintering approach results in more uniform heating, lower pore coarsening with cost-effective and energy efficiency. The chemical composition and morphology of geopolymer reinforcement was analysed by using X-ray Flourescene and Scanning Electron Microscope. The influences of the geopolymer particulates in the monolithic matrix solder on the interfacial intermetallic compound thickness and wettability were investigated by using optical microscope, while the specific value was measured by using J-image software. The melting point temperature were investigated by using differential scanning calorimeter (DSC). The influences of adding types of geopolymer particulates into Sn-0.7Cu lead free solder were investigated in terms of interfacial intermetallic compounds (IMCs) and thermal properties. It is noted that several addition of fly ash geopolymer and kaolin geopolymer particles can remarkably supressed the thickness of intermetallic layer between composite solder and the substrate and thus gives higher melting temperature but somehow certain composition resulted low in mechanical properties. Overall, the addition of 0.5 wt.% of kaolin geopolymer reinforcements into Sn-0.7Cu lead-free improved all the listed properties of the solder materials.

Investigations on the microstructure and mechanical properties of laser welded dissimilar galvanized steel–aluminum joints

In this study, galvanized high-strength steel and aluminum alloy sheets were laser-welded in zero-gap lap joint configuration. In order to determine the influences of the heat input levels, microstructural and mechanical properties of the joints were investigated. The weld bead geometry, microstructure, and intermetallic phases at the interface of welded joints were investigated using an optical microscope and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS) at different heat input levels. Mechanical properties and microhardness distribution of the welded joints were examined according to the weld bead dimension. The results revealed that there is a correlation between the weld seam geometry and intermetallic phase formation. At relatively high heat input level, the penetration depth increased, and thick Al-rich intermetallic layer was observed at the interface of the weld seam, which deteriorated the tensile strength of the joint. It has been found that without the need for any additional precaution, the thickness of the IMC layer can be limited to 5–15 μm when the optimum welding parameters were conducted. The experimental results showed that with limited heat input and penetration depths, up to 108.7-N/mm tensile strength could be achieved and fracture initiated at the weld seam–steel interface.

Microstructure and wear characterization of AA2124/4wt.%B4C nano-composite coating on Ti−6Al−4V alloy using friction surfacing

Abstract This work is focused on developing AA2124/4wt.%B 4 C nano-composite coatings on Ti−6Al−4V using friction surfacing to improve the wear resistance. The composite was produced using conventional stir casting method and coatings were laid using an indigenously-developed friction surfacing machine. The rotational speed of the mechtrode was varied. The microstructure of the composite coating was observed using conventional and advanced microscopic techniques. The sliding wear behavior was evaluated using a pin-on-disc apparatus. The coating geometry (thickness and width) increased with increased rotational speed. The interface was straight without thick intermetallic layer. Homogenous distribution of nano B 4 C particles and extremely fine grains was observed in the composite coating. The interfacial bonding between the aluminum matrix and B 4 C particles was excellent. The composite coating improved the wear resistance of the titanium alloy substrate due to the reduction in effective contact area, lower coefficient of friction and excellent interfacial bonding.