Solution Strengthening Research Articles

Microstructure characterization and age hardening response of Mg-8Sn-2Al alloy with Bi, Ag addition

The effects of Bi and Ag addition on the microstructure and age hardening response of Mg-8Sn-2Al alloy were investigated in this study. The Mg2Sn phase distributed along grain boundaries was observed in as-cast Mg-8Sn-2Al alloys and disappeared after solution treatment due to the Sn dissolution into ɑ-Mg matrix. However, a majority of Mg2Sn phase disappeared and few Mg2Sn particles still existed in the solid solutioned Mg-8Sn-2Al alloys containing Bi element. Mg2Sn precipitates formed in all peak-aged alloys. And Al, Bi and Ag elements are enriched in the areas of lath-shaped and spherical Mg2Sn precipitates in peak-aged Mg-8Sn-2Al-1.5Bi-1Ag alloy. Bi and Ag elements can act as heterogeneous nucleation sites and restrict the growth of precipitates to improve the age hardening response of Mg-8Sn-2Al alloy. Meanwhile, the undissolved Mg3Bi2 phase or early precipitated Mg3Bi2 phase during ageing treatment probably change the morphology and elements distribution of Mg2Sn precipitates. In addition, Ag and Bi atoms play a role on grain refinement and solution strengthening in Mg-8Sn-2Al alloy. Therefore, the micro-hardness value of peak-aged Mg-8Sn-2Al-1.5Bi-1Ag alloy increased to 69.9 HV from 47.4 HV of solid solutioned Mg-8Sn-2Al alloy. The precipitation behaviour, refined second phase, grain refinement and solute atoms synergistically made contributions to the strength improvement. The roles of Bi and Ag elements on improving age hardening response and precipitates characteristics are discussed in this study, which provides an important reference for exploring aged Mg-Sn alloys.

Effect of partitioning treatment on the strengthening and plasticising mechanism of one-step quenching and partitioning steels

The effects of partitioning temperature and time on the strengthening and plasticising mechanism of a one-step quenching and partitioning (Q&P) steel were investigated. The results show that as the partitioning temperature decreased, the lath martensite became finer with higher dislocation density, while the dislocation density and RA amount decreased with increasing partitioning time. Lower quenching temperature and shorter partitioning time are conducive to achieve the high ultimate tensile strength of 1377 MPa and the better total elongation of 12.3% for low-carbon one-step Q&P steels. Meanwhile, the dislocation strengthening caused by martensite and the solid solution strengthening are main strengthening mechanisms of one-step Q&P steels. In addition, a new martensite transformation kinetic model considering the influence of silicon element was established, and simultaneously, the modified CCE model predicted RA fractions more accurately for high-silicon Q&P steels, especially at lower quenching temperature.

Effect of cladding speed on the microstructure and hardness of high-hardness B-bearing Cr17Ni2 coating

The B-bearing iron-based coating produced by laser cladding exhibits super-high hardness. However, the strengthening mechanism of B-bearing Cr17Ni2 coating and non-equilibrium phase transformation during the cooling stage require further investigation. The study focused on the B-bearing Cr17Ni2 coatings produced by laser cladding at four speeds ranging from 10 mm/s to 200 mm/s. The results show that the thickness of the single layer in the coatings gradually decrease as the increase of scanning speed. The secondary dendrite arms spacing and grain size also decrease with increasing scanning speed. The microstructure of the coating consists of a martensitic phase and a eutectic phase consisting of Cr2B compounds and austenite. Combined with G\\R diagram and finite element analysis, the microstructure refining mechanism of the coating has been concluded. The effect of fine grain strengthening, solid solution strengthening, precipitation strengthening, and dislocation strengthening on hardness is investigated. It has been observed that the coating hardness increases with increasing scanning speed. This change in the hardness of the coatings is mainly because of the grain and precipitate refining.

Achieving enhanced tensile strength-ductility synergy through phase modulation in additively manufactured titanium alloys

The quest for titanium alloys with an optimal combination of tensile strength and ductility is paramount for their application in critical industries. Additive manufacturing (AM) offers a unique avenue to control the alloy's microstructure, thereby modulating its mechanical properties. This study presents a comprehensive investigation into the phase modulation strategies in AM-processed titanium alloys to achieve a synergistic improvement in tensile strength and ductility. The advancements in this work have enabled the progressive evolution of titanium alloy microstructures with addition of β stable elements, transitioning from near α-Ti alloys to α+β alloys, and finally to near β-Ti alloys. This approach has led to a significant enhancement in the tensile strength of as-prepared titanium alloys, complemented by a moderate retention of ductility. The primary contributors to this mechanical property improvement are identified as solid solution strengthening, grain refining strengthening, and grain boundary strengthening, all of which are facilitated by strategic phase modulation. Moreover, the generation of refined α lamellas, equiaxed α phases, and discontinuous grain boundary α phases has been shown to be instrumental in promoting coordinated deformation within the alloy, thus enhancing the overall ductility. Varying fracture modes demonstrated the potential of microstructure tailoring via multi-eutectoid elements alloying, facilitating the in-depth understanding of crack initiation, propagation, and strain-to-failure, shedding the lights on the enhancement of strength-ductility synergy.

Influence of Si Addition on the Microstructures, Phase Assemblages and Properties in CoCrNi Medium-Entropy Alloy.

The effects of Si addition on the microstructures and properties of CoCrNi medium-entropy alloy (MEA) were systematically investigated. The CrCoNiSix MEA possesses a single face-centered cubic (FCC) phase when x is less than 0.3 and promotes solution strengthening, while the crystal structure shows a transition to the FCC+σ phase structure when x = 0.4 and the volume fraction of the σ phase increases with a microstructure evolution as the Si content increases. The Orowan mechanism from σ precipitation effectively enhances the strength, hardness, and stain hardening of CrCoNiSix MEA, which also exhibits superior hardness at high temperatures. Furthermore, a large amount of σ phase decreases the wear resistance because of the transformation of the main wear mechanism from abrasion wear for σ-free CrCoNiSix MEA to adhesion wear for σ-contained CrCoNiSix MEA. This work contributes to the understanding of the effect of Si addition on FCC structured alloys and provides guidance for the development of novel Si-doped alloys.

Counter-intuitive mechanical performance variation in aged low-temperature interconnections in electronic packaging

Different from the conventional aging induced continuous mechanical performance deterioration in solder joints, a counter-intuitive “decrease-increase-decrease” variation in shear strength with a peak value 12 MPa higher than the initial state was captured in aged low-temperature BGA structure Cu/Sn–58Bi/Cu solder joints. The first decrease in shear strength was dominated by the coarsening of Sn and Bi phases. The following increase in shear strength was rooted in the concurrent Bi subgrain strengthening, solid solution strengthening of Bi element in Sn-rich phase and precipitation strengthening induced by the Bi-rich phase particles. The eventual decrease in shear strength was ascribed to severely deteriorated interface between the solder matrix and intermetallic compound layer being the weaker site in the long time aged solder joint. This aging induced strengthening phenomenon is inspiring in mechanical performance optimization and reliability elevation of SnBi-based solder joints for the coming chiplet and heterogeneous integration packaging.

Impact of Aging Time on the Metallurgical Properties and Hardness Characteristics of an Al-Si-Mg-Cr Hypoeutectic Alloy Intended for Automotive Applications

This research investigates the microstructural evolution and mechanical properties of LM25 (Al-Si-Mg) alloy and Cr-modified LM25-Cr (Al-Si-Mg-Cr) alloy. Microstructural analysis reveals distinctive ε-Si phase morphologies, with Cr addition refining dendritic structures and reducing secondary dendrite arm spacing in the as-cast condition. Cr modification results in smaller-sized grains and a modified ε-Si phase, enhancing nucleation sites and reducing ε-Si size. Microhardness studies demonstrate significant increases in hardness for both alloys after solutionising and aging treatments. Cr-enriched alloy exhibits superior hardness due to solid solution strengthening, and prolonged aging further influences ε-Si particle size and distribution. The concurrent rise in microhardness, attributed to refined dendritic structures and unique ε-Si morphology, underscores the crucial role of Cr modification in tailoring the mechanical properties of aluminium alloys for specific applications.

The effect of nitrogen on the tensile strength of Ti–22Al–25Nb alloy using laser beam powder bed fusion

Titanium-aluminum (TiAl) based alloys have a wide application prospect in aerospace and auto-industry fields due to low density, good physical and mechanical performances. However, the mechanical strength of TiAl-based alloys is also put forward more stringent requirements with the complexity of the application conditions. In this work, an argon-nitrogen (Ar–N2) reactive atmosphere was designed to achieve nitrogen interstitial solid-solution strengthening of Ti–22Al–25Nb alloy during the laser beam powder bed fusion (PBF-LB) process. An in-depth microstructure and mechanical performance analysis for the as-printed sample under various atmosphere conditions were performed via scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). The nitrogen atoms can be dissolved in the octahedral gap of the β phase through the PBF-LB in the Ar–N2 atmosphere, and a small amount of nitride was detected when the volume ratio of Ar to N2 was 95:5. Compared with 100 vol% Ar atmosphere condition, finer grains of the β phase can be obtained after using the mixed gas atmosphere, and the ratio of the O phase was significantly reduced. The yield strength and ultimate tensile strength can be increased from 932 MPa to 947 MPa–1080 MPa and 1099 MPa at room temperature, respectively. At the same time, the elongation reaches ∼11 % while obtaining higher tensile strength. The strength of as-printed Ti–22Al–25Nb alloy was improved by adopting a practical methodology without sacrificing plasticity.

Mesoscopic characteristics, microstructure evolution, friction mechanisms, and corrosion behavior of Ni60-SiCp coatings fabricated by laser-based directed energy deposition

The influence of varying SiCp on the mesoscopic characteristics, microstructural evolution, microhardness, frictional mechanisms, and corrosion resistance behavior of laser-based directed energy deposition Ni60-SiCp composite coatings was investigated. Coatings reinforced with varying SiCp, the innovative concept of the ''Temperature-SiCp joint effect'' mechanism was proposed. The microstructure was progressively refined due to the SiCp, while microhardness was affected by the solid solution strengthening and diffusion strengthening effects of high SiCp. Furthermore, based on wear scar morphologies, wear scar EDS analysis, and wear mechanism modeling, the frictional mechanisms were elucidated. Simultaneously, a clear understanding of the relationship between SiCp and corrosion behavior were established. It is evident that the analysis of SiCp reinforcement content in composite holds significant guiding significance.

Cr content dependent lattice distortion and solid solution strengthening in additively manufactured CoFeNiCrx complex concentrated alloys – a first principles approach

In the previous study, the authors reported that multicomponent CoFeNiCrx (x = 0, 12, 18, 24 at%) complex concentrated alloys fabricated through laser directed energy deposition experienced a substantial reduction in the saturation magnetization (Ms) and the Curie transition temperature (Tc) with the increase in Cr content. The present investigation additionally explores the effect of Cr concentration on the structural and strengthening behavior in laser directed energy deposition processed CoFeNiCrx alloy system. The novel approach adopted in the present work included the integration of experimental and computational efforts involving laser direct energy deposition (L-DED) based synthesis/fabrication of a series of new CoFeNiCrx alloys through in-situ compositional tuning which is often difficult using conventional techniques and prediction of mechanical properties of these compositionally tuned alloys using a computational methodology based on the density functional theory (DFT). X-ray diffraction and nanoindentation studies revealed that while there was a slight reduction in lattice parameters, the elastic modulus increased by approximately 30 % and the yield strength increased by 25 % with increasing Cr content. The density functional theory framework was employed to interpret the influence of Cr atoms on local lattice distortions and observed yield strength. The calculated local lattice distortion, in terms of first nearest neighbors, significantly increased with Cr concentration, which is attributed to the enlargement of Cr atomic radius in the alloyed multielement environment in comparison to its radius in the elemental form. This distortion at the local level caused solid solution strengthening. The theoretically predicted solid solution strengthening values using the Varvenne model are consistent with experimental results.

Effect of microstructure on wear resistance during high temperature carburization heat treatment of heavy-duty gear steel

To shorten the production cycle of heavy-duty gear steel and ensure its wear resistance, high temperature carburization, two high-temperature tempering, quenching, subzero treatment, and low-temperature tempering treatments were performed on 18Cr2Ni4WA steel in this work. The effect of surface precipitation phases and retained austenite on wear resistance after different heat treatments was studied throughout the process. The results show that an increase in the volume fraction (Vcar) and size (Dcar) of undissolved carbides and a decrease in the volume fraction of retained austenite (Vr) are beneficial to wear resistance. The Vcar increases from 3.4 % to 6.3 %, and the Dcar increases from 152 nm to 161 nm. The undissolved carbides are mainly cementite. The carbon content of retained austenite decreases from 1.02 % to 0.79 %, and Vr decreases from 40.6 % to 4.8 %. In addition, the microstrain increases from 0.386 % to 0.458 %, and the wear rate decreases from 0.49 × 10−8 mm3·N−1·mm−1 to 0.46 × 10−8 mm3·N−1·mm−1. The improvement in wear resistance is mainly attributed to solid solution strengthening of carbon atoms and precipitation strengthening of undissolved carbides.

Effect of stacking fault energy (SFE) of single crystal, equiatomic CrCoNi and Cantor alloy on creep resistance

Compared to mechanisms like solid solution strengthening, the stacking fault energy (SFE) should be considered as a further factor that influences the material properties. The effect of SFE of alloys or individual elements on strength and resistance can vary considerably. In the high-temperature regime above 700 °C, there are still significant gaps in the knowledge about the effect of the SFE on the mechanical properties of single-phase alloys. The effect of SFE on creep resistance of two face-entered cubic equiatomic medium and high entropy alloys, CrCoNi and CrMnFeCoNi, respectively, is evaluated to fill parts of these gaps. Using the Bridgman solidification process, the alloys were produced as single crystals and crept under vacuum at 700 °C up to 1100 °C. This work shows a significant impact of the lower SFE of CrCoNi on the creep behavior compared to the results of previous investigations of CrMnFeCoNi. The creep resistance of the former is higher over the complete temperature range. At very high temperatures, the strengthening effect of the stacking faults is significantly present. The formation of tetragonal stacking faults and extended dislocation nodes can be identified as the reason for this effect.

The Effect of Zr and Li on the Microstructure of AlMg5Si2Mn-Type Casting Alloys

AbstractIn the article, the authors present results of microstructural studies of Al-Mg-Si-Mn casting alloys with Zr, Li, and TiB2 additions on a broad scale. Zirconium content was set on two levels: 0.34 and 1.58 wt%, and Li was set 1.2 and 2.0 wt%. It was found that the addition of Zr shifts the eutectic melting temperature to a higher level, up to 611.3 °C at 1.6 wt% Zr. At the same time, Li addition leads to the depression of eutectic melting temperature: down to 587.2 °C at 2.0 wt% Li, what is a common effect of eutectic modification which was confirmed by means of structural examinations. The complex addition of Li and AlTi5B1 resulted in a eutectic melting temperature close to the equilibrium eutectic temperature for the Al-Mg-Si system (596.2 °C). The grain refinement effect of Zr is due to the nucleation of α-Al on the Zr(Al1−x, Six)3 phase. Crystals of this phase were detected in the grain centers of Zr-containing alloys. The Li addition does not affect α-Al grain size but changes the morphology of eutectic colonies from petal-like to fibrous. Observation of TiB2 particles inside the primary Mg2Si crystals gives direct experimental confirmation of nucleation of the primary phase on the surface of TiB2 in the alloy after adding Li and AlTi5B1. Natural aging of the alloys resulted in the formation of fine precipitates detected close to dislocations. The most apparent supposition is that the mechanism responsible for their formation is heterogeneous nucleation in the stress field of dislocations. Hardness tests showed adding 2.0 wt% of Li is very effective, increasing hardness up to 113 HV0.2 in naturally aged condition, which is nearly double that of commercial Al-Mg-Si die-casting alloy. Several effects were proposed which may synergistically contribute to the rise of hardness in Li-containing alloys, such as solid solution strengthening, formation of primary LiAlSi phase and natural aging.

Modulus-mismatch strategy optimized lightweight refractory high-entropy alloys for superior synergy of mechanical properties and thermostability

Lightweight refractory high-entropy alloys (LRHEAs) have received significant attention due to their excellent strength-plasticity matching. Generally, its strengthening mechanism mainly comes from solid solution strengthening caused by atomic radius mismatches, but excessive atomic radius mismatch can reduce the phase stability of solid solution and easily generate precipitated phases to reduce the plasticity. Here, we present a strategy to enhance the shear modulus mismatch while improving the mechanical properties and phase stability of LRHEAs. We chose the TiZrVNbAl system as the LRHEAs model. The addition of Mo resulted in a modulus mismatch induced strength contribution of 564 MPa, which accounts for ∼57 % of the total strength. Compared to the alloy without Mo, the strength increased by ∼42 % without any loss of ductility. More importantly, the addition of Mo significantly reduces the diffusion coefficient of the main element and realizes the effective kinetic suppression of the precipitated phase. This enables the alloy to avoid brittle precipitate generation even after aging at 500 °C for 5 h, and hence the excellent mechanical properties are well kept. Additionally, the strength of the LRHEA is increased by more than two times at 700 °C, demonstrating higher high temperature performance compared to RHEAs with tensile ductility. Utilizing the shear modulus mismatch strategy can effectively enhance the solid solution strengthening effect, improving the comprehensive mechanical properties of the alloy at room temperature and high temperature, while also improving phase stability. This provides a new approach to developing structurally stable high-performance alloys.

Overcoming strength-ductility trade-off in Si-containing transformation-induced plasticity high-entropy alloys via metastability engineering

Benefiting from the transformation-induced plasticity effect has been recognized as a new approach to develop high-performance Si-containing high-entropy alloys with outstanding room-temperature strength-ductility balance. However, closely controlling the kinetics of deformation-induced α΄-martensite formation is essential to further boost ductility in addition to ultrahigh strength. In the present work, this aim was fulfilled by manipulating the chemical composition of the promising FeCoCrVMnSi system with the replacement of Mn with Ni and adjusting the Si content to fine-tune the stacking fault energy and the driving force of austenite to martensite transformation. The experimental results were obtained by EBSD, TEM, XRD, and tensile testing, and the results were supported by thermodynamic calculations, work-hardening analysis, and assessment of α΄-martensite formation kinetics. Accordingly, the single-phase Fe47Co30Cr10Ni5V8-xSix system was designed. In this system, the Fe47Co30Cr10Ni5V2Si6 alloy exhibited exceptional tensile strength (∼1.1 GPa) and total elongation (72 %), outperforming the competitive dual-phase Fe46Co30Cr10Mn5V2Si7 alloy. High strength was attributed to the high solid-solution strengthening effect as well as the volume fraction of α΄-martensite, while its ductility benefited from fine-tuned kinetics of martensitic phase transformation.

Development and characterization of novel Mg-6Zn-0.6Si-xSn alloys with varying Sn addition

In this study, the role of varying Sn concentration (x = 0, 1, 2, 3 and 4 wt%) on the microstructure and mechanical properties of Mg-6Zn-0.6Si-xSn alloys has been investigated. The type, distribution and volume fraction of the precipitates have been carried out using both scanning electron microscopy (2D) and X-ray tomography (3D). The Mg2Sn phase appeared after addition of 2 wt% Sn. The increase in the compressive strength of the alloy with increase in Sn addition has been attributed to both precipitation strengthening as well as solid solution strengthening.

Microstructure, mechanical properties and multiphase synergistic strengthening mechanisms of LPBF fabricated AlZnMgZr alloy with high Zn content

In this work, a novel aluminum alloy with high Zn content was designed for laser powder bed fusion (LPBF) forming process. Aluminum alloy powder containing 14 wt% Zn and 2 wt% Zr was produced to conduct LPBF experiments with different process parameters. The analysis of the specimens revealed that the up facing surface exhibited an average microhardness peak value of 170.6 HV, achieving the ultimate tensile strength (UTS) of 573 MPa and the elongation of 11.6 %. There was no significant change in grain size and a large amount of plate-like η' (a metastable precipitate MgZn2 phase) phase precipitated within the grains after aging treatment (120°C, 21 h). The specimen reached the average microhardness peak of 181.7 HV and the UTS of 605 MPa. The principal strengthening mechanisms in the LPBF-formed samples were solid solution strengthening and grain refinement strengthening. After aging treatment, the precipitation of the second phase from solute atoms led to grain refinement strengthening and second-phase strengthening becoming the predominant factors to enhance the sample's strength. Al14ZnMgZr alloy have great application prospect in high strength and tough service environment.

Improving mechanical properties of W-Ni3Al alloy through Zr element addition: Solid-solution and oxide particle strengthening

In this study, fine Ni3Al flakes facilitated the W-Ni3Al alloy liquid phase sintering, while the added 0.9 wt% Zr element enhanced its mechanical properties, finally obtaining the 1200 °C sintered W-Ni3Al-Zr alloy (WNZ-1200 alloy) with excellent comprehensive properties. Specifically, the relative density, tungsten grain size, bending strength, and macro hardness of WNZ-1200 alloy were 98.26 ± 0.31 %, 3.06 ± 0.65 µm, 1472.56 ± 61.90 MPa, and 76.10 ± 0.82 HRA, respectively. By analyzing the alloy’s phase and microstructure, its excellent mechanical properties were originated from the formed Ni3(Al, W, Zr) solid solution, unique nano-Al2O3 ‘rivet’, the semi-coherent interface of W/t-ZrO2, oxide dispersion strengthening, and the t-ZrO2 phase transformation strengthening.

Developing Zn-2Cu-xLi (x < 0.1 wt %) alloys with suitable mechanical properties, degradation behaviors and cytocompatibility for vascular stents

Biodegradable Zn alloys show great potential for vascular stents due to their moderate degradation rates and acceptable biocompatibility. However, the poor mechanical properties limit their applications. In this study, low alloyed Zn-2Cu-xLi (x = 0.004, 0.01, 0.07 wt %) alloys with favorable mechanical properties were developed. The microstructure consists of fine equiaxed η-Zn grains, micron, submicron-sized and coherent nano ε-CuZn4 phases. The introduced Li exists as a solute in the η-Zn matrix and ε-CuZn4 phase, and results in the increase of ε-CuZn4 volume fraction, the refinement of grains and more uniform distribution of grain sizes. As Li content increases, the strength of alloys is dramatically improved by grain boundary strengthening, precipitate strengthening of ε-CuZn4 and solid solution strengthening of Li. Zn-2Cu-0.07Li alloy has the optimal mechanical properties with a tensile yield strength of 321.8 MPa, ultimate tensile strength of 362.3 MPa and fracture elongation of 28.0 %, exceeding the benchmark of stents. It also has favorable mechanical property stability, weak tension compression yield asymmetry and strain rate sensitivity. It exhibits uniform degradation and a little improved degradation rate of 89.5 μm∙year−1, due to the improved electrochemical activity by increased ε-CuZn4 volume fraction, and generates Li2CO3 and LiOH. It shows favorable cytocompatibility without adverse influence on endothelial cell viability by trace Li+. The fabricated microtubes show favorable mechanical properties, and stents exhibit an average radial strength of 118 kPa. The present study indicates that Zn-2Cu-0.07Li alloy is a potential and promising candidate for vascular stent applications. Statement of significanceZn alloys are promising candidates for biodegradable vascular stents. However, improving their mechanical properties is challenging. Combining the advantages of Cu and trace Li, Zn-2Cu-xLi (x < 0.1 wt %) alloys were developed for stents. As Li increases, the strength of alloys is dramatically improved by refined grains, increased volume fraction of ε-CuZn4 and solid solution of Li. Zn-2Cu-0.07Li alloy exhibits a TYS exceeding 320 MPa, UTS exceeding 360 MPa and fracture EL of nearly 30 %. It shows favorable mechanical stability, degradation behaviors and cytocompatibility. The alloy was fabricated into microtubes and stents for mechanical property tests to verify application feasibility for the first time. This indicates that Zn-2Cu-0.07Li alloy has great potential for vascular stent applications.

Comparative Analysis of Wear Behavior of High Entropy Alloy (TiVNbCrAl) and Ti-based Conventional Alloy (TiNbCrCoAl)

This research examined the relationships between processing, structure, and property at both room temperature and increased temperature for two BCC high entropy alloy (TiVNbCrAl) and Ti-based conventional alloy (TiNbCrCoAl) prepared using standard arc melting. Both alloys have been determined to have the BCC single-phase solid solution structure. To investigate the hardness and tribological behavior and processes at room temperature and above, microindentation and sliding wear experiments were undertaken. Both alloys display comparable friction behavior when sliding at room temperature, with an average steady-state coefficient of friction (COF) of 0.6. When sliding temperatures rise to 302 °C, the average COF for HEA (TiVNbCrAl) has decreased to a lowest value of ~0.4 due to the creation of a persistent tribochemical layer made of Nb and Cr oxides amid the sliding surfaces, which lowers COF. Whereas, COF for Ti-based conventional alloy remains at higher values of ~0.65. Mechanistic wear analyses revealed that the formation of tribofilms with low interfacial shear strength inside the wear tracks was the cause of this. The tribofilms were identified to be mostly constituted by multi-element solid solution oxides, such as Ni2O5, Cr2O3, and NiO2, according to Raman spectroscopy. The Vickers microharness values for Ti-based conventional alloy is about 365±4 HV. Whereas, for high entropy alloy is about 572±12 HV due to the solid solution strengthening.