Increasing Si Content Research Articles

Development of Mischmetal-(FeCo)-B Ribbons with Improved Magnetic Properties by Addition of Si

In order to develop mischmetal-based permanent magnets with a high performance/cost ratio, Si addition was employed to enhance the magnetic performance of the MM16Fe76-xCo2SixB6 (x = 0–1.5%) ribbons. The ribbons were manufactured by a melt-spinning technique at different velocities. Samples were studied in an as-cast state and after annealing. It was found that the addition of Si in the MM16Fe76-xCo2SixB6 ribbons increased the exchange interaction between Fe atoms in the 2:14:1 phase, reduced the crystal grain size, and increased the exchange coupling between the crystal grains; as a result, the magnetic properties were improved. The coercivity and Curie temperature increased with the increasing Si content from x = 0 to x = 1.5 at%, while the remanence and energy product increased with the addition of Si up to 1% and decreased with further Si addition. The best combination of magnetic properties, such as coercivity of Hc = 8.9 kOe, remanence Mr = 98 emu/g, Curie temperature Tc = 257 °C, and energy product (BH)max = 13.84 MGOe, were obtained in ribbons with 1.0 at. % Si. Thus, it is demonstrated that the addition of Si leads to an improvement of the magnetic properties of MM16Fe76-xCo2SixB6 ribbons, making them good candidates as precursors for the preparation of permanent magnets with an energy product between that of ferrites and Nd-Fe-B magnets.

Microstructure evolution of FD-POEM powders during high-temperature plasma spheroidization

The freeze–dry pulsated orifice ejection method (FD-POEM) can be coupled with plasma spheroidization (PS) as an advanced approach for fabricating spherical refractory powders used in laser additive manufacturing. However, the microstructure evolution of FD-POEM powders, which include components of various melting points, during ultrahigh-temperature PS treatment remains unclear. In this work, the morphology, chemical composition, and microstructure of MoSiBTiC alloy powders, as representative PS powders, were systematically investigated. The mesh-structured FD-POEM powders underwent complete densification, resulting in a 52 % reduction in particle size. The PS powders were composed of coarse solid solution Mo (Moss) and fine eutectic Mo5SiB2/TiC phases, consistent with the composition of additively manufactured MoSiBTiC alloys. With an increase in Si content, the volume fraction of fine Mo5SiB2 phases increased, resulting in increased Vickers hardness. Notably, the oxygen content of FD-POEM powders decreased by > 99 %, owing to the effective elimination of surface oxides on the initial elemental powders during ultrahigh-temperature PS treatment. This research provides an innovative approach for reducing the oxygen content in refractory powders to be used for additive manufacturing. Enhanced understanding of the microstructure evolution of PS powders can facilitate the composition optimization of refractory powders and development of a microstructure–property database for additively manufactured materials.

Influence of Si Addition on the Chemical and Tribological Performance of TiAlCrN Coating Deposited by Co-Sputtering

In this work, nanostructured TiAlCrN coatings were deposited on a WC-Co substrate using a co-sputtering process varying the silicon composition on the coatings. The influence of silicon content on the mechanical, chemical, and tribological performance of the coatings was studied. The hardness increases from 11 to 16 GPa with the Si content; also, Young’s modulus increases from 260 to 295 GPa. The H/E ratio, which is a measure of materials’ ability to take the strain before deformation, is also increased with the increase in Si content, suggesting increased toughness. XPS analysis reveals that the coatings present titanium, aluminum, chromium, and silicon nitrides. The tribological behavior of the coatings was conducted through ball-on-disc tests, in which the results show that the coefficients of friction range from 0.15 to 0.55, with the lowest for the samples with the highest Si content. This behavior is benefited by the formation of oxynitride species, identified by XPS, which acts as lubricating layers and diffusion barriers. TiAlCrSixN coating presents a potential application for severe wear owing to its tribological performance.

Influence of Si content on thermoelectric properties of Mg2(Sn,Si) films by sputtering

Mg2(Sn,Si) films with different Si content were prepared by magnetron sputtering. The phase composition, surface and cross-sectional morphology, chemical composition and element distribution, carrier concentration, carrier mobility, electrical conductivity, Seebeck coefficient and power factor of the deposited Mg–Sn–Si films were studied. The results show that the deposited films are composed of Mg2(Sn,Si) solid solution phase and a small amount of metal Mg phase. The room temperature carrier concentration decreases and mobility increases with increasing Si content in deposited Mg–Sn–Si films, respectively. The room temperature electrical conductivity and Seebeck coefficient decreases and increases with increasing Si content, respectively. The deposited Mg2(Sn,Si) films with moderate Si content possess the maximum power factor value of 2.76 mW m−1 K−2 at 303 °C and its room temperature figure of merit reaches the highest value of 0.44. The thermal conductivity decreases with increasing Si content, indicating that the lattice distortion caused by Si doping can reduce the thermal conductivity of the deposited films.

Compositional engineering of magnetic anisotropy in Cr2SixGe2-xTe6

Magnetic van der Waals (vdW) materials are highly sensitive to their chemical compositions and atomic structures, which presents rich opportunities for synthetic control of vdW ferromagnets. Here, we synthesized the quaternary alloys Cr2SixGe2-xTe6 using the flux method and discovered that the Ge:Si source ratio should be designed deliberately higher than the expected in resultant crystals due to the stronger affinity of Si than Ge to be involved in Cr2SixGe2-xTe6 reactions. Temperature-dependent magnetization and magnetic hysteresis measurements revealed that as the Si content increases, the Curie temperature decreases while the out-of-plane anisotropy increases monotonically. When x increases from 0 to 2 in Cr2SixGe2-xTe6, the out-of-plane saturation fields remain approximately unchanged at ∼0.2 T, while the in-plane saturation fields increase monotonically from 0.5 T to 1.2 T. The distinct behaviors between out-of-plane and in-plane saturation fields arise from the different mechanisms underpinning the two fields – the out-of-plane saturation field is determined by the competition of exchange interaction, magnetic anisotropy, and dipolar interaction, whereas the in-plane saturation field by magnetic anisotropy. Our compositional engineering provides a fundamental understanding of the layered magnetic materials and insightful guidance for the future design of vdW magnets.

Effects of silicon and neodymium additions on microstructures and mechanical properties of CoCrNi medium entropy alloy films

A series of (CoCrNi)100–x–ySixNdy medium entropy alloy films (MEAFs) with manipulated metalloid element, Si, and rare earth element, Nd, was synthesized using magnetron three-target co-sputtering. A transition from single FCC phase to the coexistence of FCC CoCrNi, HCP CoCrNi and HCP NdNi5 phases was observed in XRD and TEM diffraction patterns with the increasing Nd content for Si content of ∼0.7 at.%, and the SEM and TEM images showed the refined columnar grains. The hardness and compressive yield strength reached the maxima of 10.29 and 4.27 GPa, respectively, in Si0.61Nd5.14 film due to the solid solution strengthening, grain refinement and precipitation strengthening. However, The films exhibited a transition from fully crystalline to crystalline within the amorphous matrix in XRD and TEM results with the increasing Si content for Nd content of ∼2.6 at.%, and the columnar structure disappeared in the SEM and TEM images. The hardness and yield strength increased slightly to the maxima of 9.75 and 4.10 GPa, respectively, in Si0.76Nd2.91 film attributed mainly to the interstitial solid solution strengthening. Discussion on (CoCrNi)100–x–ySixNdy MEAFs showed the optimized mechanical properties in Si0.61Nd5.14 film, indicating that precipitation strengthening and grain refinement could be the major strengthening mechanisms in this system.

Effects of in situ Mg-Sialon and β-Sialon on the microstructure and properties of MgAl2O4-SiC composites

MgAl2O4-SiC composites were prepared under flowing nitrogen at 1500 °C by using MgAl2O4 powder, SiC powder, Al powder and Si powder as raw materials. Through microstructural observation and analysis, the effects of in situ Mg-Sialon and β-Sialon with different amounts of Si powder addition were investigated in this paper. The results show that the samples without Si addition main contained MgAl2O4, SiC and well development plate structure Mg-Sialon phase. After addition of Si powder, not only the above three phases appeared, but also β-Sialon phase appeared. Meanwhile, with increasing Si contents, the content of β-Sialon phase increased and samples were more dense, limiting the development of the plate structure Mg-Sialon phase. With increasing Si content from 0 wt% to 20 wt%, the apparent porosity shows decreased trend, while the bulk density and cold module of rupture show increased. The samples with 20 wt% Si addition can get the minimum apparent porosity (33.5 %), maximum bulk density (2.13 g•cm−3) and cold module of rupture (87.0 MPa). Besides, the formation mechanism of Mg-Sialon and β-Sialon was discussed in detail and the role of Si was elucidated.

Effect of the Si Content on the Dry and Wet Sliding Wear Behavior of the Developed Ti-15Mo-(0-2) Si Alloys for Biomedical Applications

The durability of a metallic biomaterial to withstand weight loss is a key factor in determining its service life and performance. Therefore, it is essential to create biomaterials with high wear resistance to ensure the biomaterial has a long service life. Thus, this study aims to explore the dry and wet sliding wear characteristics of the developed Ti-15Mo-xSi as-cast alloys (where x equals 0, 0.5, 1, 1.5, and 2 wt.%) in order to assess the impact of the Si addition on the microstructure, mechanical properties, and wear resistance and to consider them for biomedical applications. The wear experiments were conducted using a pin-on-desk wear testing machine at a load of 20 N and a sliding distance of 1000 m with and without applying simulated body fluid (SBF). Different techniques were utilized in the evaluation of the developed Ti-15Mo-xSi alloys. The results showed that significant grain refining was attained with the Si addition. The hardness, compressive strength, and wear resistance of the Ti-15Mo-xSi as-cast alloys increased with the increase in Si content. The Ti-15Mo-2Si as-cast alloy exhibited the highest dry and wet wear resistance of all the Ti-15Mo-xSi alloys. The worn surfaces were investigated, the roughness and main features were reported, and the wear mechanisms were also discussed.

Unraveling the effect of pressure on structural phase transition, electronic, and optical properties of Hf1-xSixO2 (x = 0, 0.03, 0.06, 0.09): A first-principles investigation

The non-centrosymmetric phase of HfO2 with excellent Si compatibility has great importance in integrated photonic circuits, non-volatile memory, and ferroelectric field effect transistors. We report a theoretical study of pressure-induced phase transition from a centrosymmetric m-HfO2 to non-centrosymmetric o-HfO2 with Si doping. The reported phase transition pressures, i.e. 15, 14, 8, and 8 GPa for x = 0, 0.03, 0.06, and 0.09, respectively, for Hf1-xSixO2 are in excellent agreement with available experimental results. With increasing Si concentrations, the transition pressures reduce significantly, which is explained in terms of bond length and charge transfer. The thermal stability of the obtained o-HfO2 phase is examined via ab-initio molecular dynamics up to its synthesis temperature. The negative formation energy also confirms its thermodynamical stability. Density of states indicates the noticeable appearance of Si states in the lower conduction band and an increase in the extent of hybridization between Hf-5d, O-2p, and Si-2p atomic states. The doping changes the nature of band gap from indirect to direct, concurrently reducing the magnitude. The o-HfO2 shows a low value of static dielectric constant, which results in a smaller refractive index (1.82) and lower reflectivity in the infrared and visible regions.

Diffusion Behavior of Carbon and Silicon in the Process of Preparing Silicon Steel Using Solid-State Decarburization

In this study, we investigated the relationship between the decarburization effect of the solid-state decarburization method for preparing silicon steel and the atomic diffusion behavior in the matrix, focusing on 1 mm thick Fe-0.18 wt% C-Si (1.5, 3.5 wt%) alloy strips as the research object. Solid-state decarburization experiments were carried out in an Ar-H2O-H2 atmosphere, and the self-diffusion behavior of C and Si in Fe-C-Si alloy system was simulated by molecular dynamics. The results show that the molecular dynamics simulation results are consistent with the decarburization experimental results. When the temperature is lower than 800 °C, the atoms maintain a compact bcc structure, so the migration rate of carbon is low. When the temperature rises, the atoms move violently, resulting in the destruction of the crystal structure. Because the atomic arrangement tends towards a disordered structure, the migration rate of C is high and the diffusion coefficient increases. The experimental results showed that the decarburization rate was accelerated. At the same temperature, the diffusion activation energy Q = 48.7 kJ·mol−1 of carbon in an Fe-3.5 wt% Si-C alloy matrix can be calculated. The diffusion activation energy of carbon Q = 47.3 kJ·mol−1 was calculated using a molecular dynamics simulation. When the content of Si is 3.5 wt% and 1.5 wt%, the diffusion series of Si can be expressed as D3.5Si, Si = 8.54 × 10−10 exp(−33,089.7/RT) m2/s and D1.5Si, Si = 2.06 × 10−9 exp(−46,641.5/RT) m2/s, respectively. When the Si content is 3.5 wt%, the diffusion coefficient of Si is larger. After diffusion to the near surface, it combines with the remaining O to form a continuous strip of SiO2. When the Si content is 1.5 wt%, the diffusion coefficient of Si is small. The remaining O diffuses in the matrix and will oxidize when encountering Si; it cannot aggregate in a highly-dispersed distribution. The lattice transition from face centered cubic lattice austenite to body centered cubic lattice ferrite occurred in the matrix of the thin strip. The diffusion coefficient of C in ferrite is much larger than that in austenite. Therefore, the decarburization rate suddenly increases before decarburization stagnation. With the increase in Si content, the diffusion activation energy of C decreases, which promotes the decarburization effect.

Impact of Deep Seawater on the Electrochemical Corrosion Performance of Hypoeutectic, Eutectic and Hypereutectic Al-Si Automotive Alloys

Corrosion of aluminum alloys is a significant concern for shipbuilders to ensure the longevity of ocean vessels and equipment. Hence, the study aims to evaluate the corrosion performance of Al-Si as automotive alloys with varying concentrations of Si in deep seawater using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The surface condition prior to corrosion, as well as after corrosion, is analyzed using optical and scanning electron microscopy. The entire test is performed at an ambient condition. The results demonstrate that the corrosion resistance improves in alloys with increasing amounts of Si near the eutectic level, after which the corrosion protection deteriorates. Higher Si concentrations show higher values for polarization resistance and open circuit potential. In contrast, corrosion current and corrosion rate values decrease with increasing Si concentration up to eutectic composition. Si assists the formation of SiO2 and MgO films through Mg2Si intermetallics along with the Al2O3 on the surfaces, which aids in corrosion resistance. Optical and scanning electron micrographs reveal the presence of films on the surfaces after corrosion, which exhibit pits and pinholes on the surfaces of the alloys with lower Si concentrations. Hypereutectic alloy is affected by corrosion of its pinhole-like defects. The corresponding EDS analysis also confirms the protective layer of different oxides on the surfaces.

Effect of Si content on the microstructure and high temperature oxidation resistance of TiAlCrNiSi high-entropy alloy films synthesized by multi-target magnetron co-sputtering

In this study, we prepared TiAlCrNiSi high-entropy alloy films (HEFs) with different contents of four elements by multi-target magnetron co-sputtering with regulated sputtering power, and the elemental contents of the films all met the high-entropy range (5 at%−35 at%). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that the surface of the films was relatively smooth, the increase of sputtering power and Si element in the films reduced the roughness of the films. This demonstrates the effect of Si in refining the grains and reducing the roughness of the film. X-ray diffraction (XRD) showed that the average grain size of films decreases with the increase of Si content. This phenomenon proves that Si has the effect of refining grains and reducing the roughness of the film. The TC4 substrate and the films were treated at 700 ℃ for 50 h. It was found that TiAlCrNiSi HEFs could improve the high temperature oxidation resistance of TC4. The mechanism of oxidation resistance of the films was investigated by XRD, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM), and it was found that the generation of dense oxides Al2O3, Cr2O3 and SiO2, the grain refining effect of Si and the appearance of amorphous structure were the main reasons for the increased oxidation resistance.

Study on the influence of Al-Si welding wire on porosity sensitivity in laser welding and process optimization

Al-Si welding wire is commonly used in the aluminum alloy welding due to the excellent heat crack-resistance and corrosion-resistance, but the presence of large-sized pores hinders its widespread application in the field of laser welding. This study focuses on the cause of pores formation in the laser welding using Al-Si wires with different Si contents and investigates the dynamic behavior of laser keyhole by a high-speed camera-based molten pool monitoring system. The results showed that with the increase of wire Si content from 5% to 12% (wt.%), the keyhole stability decreased and the weld porosity increased. According to the thermodynamic calculations, the increased Si content enhanced the Reynolds number of molten pool, resulting in increased turbulence tendency. It caused the molten pool being more susceptible to external disturbances, which decreased the stability of keyhole. Furthermore, the reduced dynamic viscosity of molten pool increased both the depth-to-width ratio of keyhole and its opening and closing frequency. These combined effects ultimately contributed to the increased susceptibility to pores formation. Based on the above results, a circular oscillating laser was introduced to guide the regular flow of molten pool. The beam oscillation improved the resistance to fluctuations of molten pool and reduced the depth-to-width ratio of keyhole. Besides, the high-frequency rotating keyhole could capture and re-melt the formed pores. An optimal laser oscillating welding was determined using response surface methodology to control the porosity within the acceptable range.

Influence of Si and Mo on the Sigma-Phase Precipitation in S32750 Super Duplex Stainless Steel Slab

In this study, we investigated the effect of Si and Mo on the sigma-phase precipitation in S32750 super duplex stainless steel slab. The activity for Mo with increasing Si and Mo was calculated by the Wagner formula, and the equilibrium solidification phase diagrams of S32750 duplex stainless steels with different Si and Mo contents were calculated using the thermo-calc software. The sigma phase precipitated mainly at ferrite/austenite phase boundaries and grew up towards the interior of ferrite phase in S32750 SDSS slab. The area fraction and size of the sigma phases significantly increased with increasing Mo content and Si content. Also, the increment in Mo and Si content affected the Mo concentration in sigma phase. The sample（Mo:3.4%,Si：0.3%） had a lowest sigma-phase area fraction of 2.84% and had lowest Mo content in σ phase.The calculation results showed that the increase of Mo and Si content increased the initial precipitation temperature and maximum precipitation amount of σ phase in S32750 SDSS equilibrium phase diagram. The activity of Mo also increased with increasing Si content and Mo content. That is, Mo and Si elements promoted the precipitation of σ phase.

Influence of Al and Si concentration on the structural, electronic, magnetic, and mechanical properties of Fe2CoAl1−xSix (x = 0, 0.25, 0.5, 0.75, and 1.0) full heusler alloys: First principles calculations and Monte Carlo simulation

A comprehensive investigation into the structural, electronic, magnetic, mechanical, and thermomagnetic properties of Fe2CoAl1−xSix (x = 0, 0.25, 0.5, 0.75, and 1.0) full Heusler alloy is performed using density functional theory and Monte Carlo simulation. Pristine and doped structures are found to adopt the XA prototype, and the lattice parameter is observed to decrease with increasing Si concentration. An increase in the bulk modulus is noticed with the increase of Si concentration, the resulted values range from 160 to 240 GPa. The electronic properties reveal a band gap in the spin-down states of the pristine and doped structures using mBJ approximation. The magnetic moments of the doped structures are found to be similar to those of the pristine structures, and the exchange interaction parameters highlight the Fe-Fe interaction as the strongest in the doped structures. The resulting Curie temperature using Monte Carlo simulation ranged between 792 K and 1029 K. Finally, understanding the magnetic properties of these Heusler alloys could pave the way for spintronics and high-temperature magnetic applications.

The Influence of Heat Treatment Temperature on Tensile Properties of Metal-Bonded Diamond Composites Fabricated via Selective Laser Melting.

Selective Laser Melting (SLM) is an effective technology for fabricating new types of porous metal-bonded diamond tools with complex geometries. However, due to the high cooling rate and internal stresses during SLM fabrication, defects such as high porosities and interface gaps still need to be resolved before it can be considered for use in other applications. The influence of heat treatment temperature on internal characterization, interface microstructures, and tensile properties of AlSi7Mg-bonded diamond composites fabricated by SLM were investigated in this work. From experimental results, the porosities of HT-200, HT-350, and HT-500 specimens were 12.19%, 11.37%, and 11.14%, respectively, showing a slightly lower percentage than that of the No-HT specimen (13.34%). Here, HT represents "Heat Treatment". For No-HT specimens, an obvious un-bonding area can be seen in the interface between AlSi7Mg and diamond, whereas a relative closer interface can be observed for HT-500 specimens. After heat treatment, the elastic modulus of specimens showed a relative stable value (16.77 ± 2.79~18.23 ± 1.72 GPa), while the value of yield strength decreased from 97.24 ± 4.48 to 44.94 ± 7.06 MPa and the value of elongation increased from 1.98 ± 0.05 to 6.62 ± 0.51%. This difference can be attributed mainly to the disappearance of the solid-solution hardening effect due to the increase of Si content after heat treatment.

Microstructure and mechanical properties of in-situ Ti5Si3/TC4 composites via spark plasma sintering and hot rolling

In this study, low energy ball milling and spark plasma sintering techniques prepared the in-situ synthesized Ti5Si3 reinforced Ti-6Al-4V (TC4) matrix composites and then rolled them at high temperatures. In the composites with high Si content, the Ti5Si3 particles distributed at the interface of α-phase and β-phase agglomerated and then formed a quasi-continuous network structure, which will deteriorate the plasticity of the composites. After hot rolling, the grains of the composite were significantly refined, and more Ti5Si3 particles were precipitated. With the increase in Si content, the tensile strength of sintered composites increased slightly, but the elongation decreased greatly. After hot rolling, the tensile strength of the composite increased significantly with an increment of 359.4 MPa, among which the composite with 0.6 wt% Si achieved a synchronous increase in strength and plasticity. The strengthening mechanism of sintered composites included dislocation strengthening, solution strengthening, and grain refinement, among which dislocation strengthening and grain refinement were the main strengthening mechanisms. The strengthening mechanism of rolled composites was mainly the dislocation strengthening caused by rolling, the grain refinement, and the mismatch of thermal expansion coefficient.

Effect of heat and cryogenic treatments on the microstructure and properties of YF3 modified NiTi-Si laser cladding coatings

YF3 modification NiTi-Si coatings were prepared on Ti-6Al-4 V substrate by laser cladding. On this foundation, heat and cryogenic treatments were conducted respectively to explore the effect of after-treatment procedures. The consequence of post-treatment methods on the phase constituent, microstructure, mechanical property, and phase transition characteristics of post-treatment coatings was studied. The phase constituent of the three coatings was roughly the same, composed of NiTi and NiTi2. The results show that heat treatment led to the coarsening of NiTi phase grain size and increased Si content in the NiTi2 phase. In addition, due to the rapid cooling rate provided by cryogenic treatment, the spinodal decomposition of the Si element occurred in the NiTi2 phase. Furthermore, the post-treatments also affected the phase transformation characteristics of the coatings. As the temperature of martensitic transformation is sensitive to the content of Ni element in the NiTi phase, the Ms and Mf points of the heat treatment coating were slightly higher. In contrast to the heat treatment, the Ms and Mf points of the cryogenic treatment coating decreased. The microhardness of the three coatings is as follows: cryogenic treatment > original coatings > heat treatment. The cryogenic treatment coating has the highest microhardness due to grain refinement and spinodal decomposition. In addition, the cryogenic treatment coating showed the best wear morphology.

Revealing the effect of Si content on the microstructure and properties of Al–Si alloy by experiments and phase-field simulation

The grain size of aluminum alloy is closely related to solute content and solidification conditions. This study investigated the influence of Si content on the solidification microstructure and properties of the Al–Si binary alloy by experiments and phase field simulation. The experimental results indicated that the microstructure of Al–Si alloy changes from coarse columnar grains to uniformly distributed equiaxed grains as Si content increases from 0 to 7 wt%, and the average grain size of Al–2Si is the smallest (2.2 mm). Meanwhile, the tensile strength of Al–Si alloys increases from 56.9 MPa to 111 MPa with increasing Si content, whereas the ductility decreases from 30% to 2.5%. Moreover, high casting temperature will produce coarse columnar crystals, low casting temperature forms equiaxed crystals, the optimal casting temperature in this study is 30 °C above the liquidus. Phase field simulations reveal that the evolution of Al–Si microstructures is governed by two dimensionless parameters: the initial temperature (T0), related to casting temperature and solidification interval, and the latent heat (K1), connected to latent heat, specific heat, and solidification interval. For a certain alloy composition (Al–2Si), the grain size exhibits a non-monotonic trend, decreasing initially and then increasing as T0 increases, with an optimal T0 value of 1.42. When the Si content varies between 2 and 7 wt%, the average grain sizes decrease as K1 increases, with the maximum K1 value observed at 1.38 for Al–2Si.

FeCrMnVSix high entropy alloy coatings with improved high temperature tribological properties via synergistic effect of in situ-formed SiO2 and bimetallic oxides

The laser cladding technique fabricates the FeCrMnVSix high entropy alloy (HEA) coatings on 410 alloy substrates. Tribological tests reveal that the coefficient of friction (COF) of the FeCrMnVSix HEA coatings decreases significantly with increasing Si content. However, the wear rates of HEAs decrease and then increase with the increase of Si content, which means that the excessive Si will weaken the wear resistance of the HEAs in high-temperature environments. The FeCrMnVSi1.0 HEA coating possesses the lowest wear rate (2.26 × 10−5 mm3N−1m−1), which is 43.36 % lower than that of the substrate at 800 °C. The synergistic effect of in situ-formed SiO2 and bimetallic oxides endows FeCrMnVSi1.0 HEA coating with outstanding tribological properties.