Eutectic Structure Research Articles

Calculation and Experimental Verification of Zn–Al–Mg Phase Diagram

The liquid phase projection diagram, three-dimensional phase diagram, and vertical section diagram of the Zn–x%Al–x%Mg alloy system was calculated using the phase diagram calculation software Pandat. Simultaneously making full use of the self-developed hot-dip galvanizing process simulation machine by China Steel Research produced a 75%Zn–19%Al–6%Mg coating. A method combining phase diagram calculations and experimental verification was used to investigate the equilibrium phases and solidification process of the alloy. The microstructure of the 75%Zn–19%Al–6%Mg coating was studied using scanning electron microscopy and energy dispersive spectrometry. The results indicate that the coating structure consists of primary Al dendrite phase, MgZn2 inter-metallic compound and Zn-rich phase. There is no ternary eutectic structure in the coating structure. Al dendrites grow on the surface of the coating, while there are no Al dendrites on the cross-section. The experimental results strongly concur with the calculated results from the Pandat phase diagram. The solidification sequence of the 75%Zn–19%Al–6%Mg coating is L→L + Al→L + Al + MgZn2→Al + MgZn2 + Zn. The phase diagram guides industrial production significantly, avoiding the waste of transitional materials and zinc caused by small scale trial and error experiments, thus reducing unnecessary production costs. The factory can select a reasonable coating composition designing scheme in the phase diagram, based on the performance requirements of customers for the coating.

Solidification evolution and corrosion performance of CoCrFeNiBx eutectic high entropy alloy coatings

CoCrFeNiBx (x = 0.15, 0.30, 0.45, 0.60, 0.75) eutectic high entropy alloy (EHEA) coatings, abbreviated as B0.15–B0.75, were prepared by laser cladding. The inevitability of solid-state phase transition in B0.75 coating has been verified from the perspective of enthalpy. The solidification and crystallization process and laws of the CoCrFeNiBx coatings were obtained by observing the phase and microstructure, combining the DSC testing and analysis. When the mole ratio of B atoms x ≤ 0.45, the FCC1 phase solidifies into dendrites, and the eutectic structure composed of the coupling of FCC1 and FCC2 lamellae forms between dendrites. As the content of B increases, the proportion of eutectic structure rises steadily while the dendrites refine and decrease. When x = 0.60, the B content reaches the eutectic point, forming the eutectic structure with a feathery appearance. When x = 0.75, a strip-shaped boride structure will also precipitate after the formation of the metastable eutectic structure. The B element can promote the formation of eutectic structures, thereby improving the microhardness of the CoCrFeNiBx coatings from 267.0 HV0.2 to 555.4 HV0.2. However, as the B content rises, the corrosion current density of the CoCrFeNiBx coating in 3.5 % NaCl solution decreases from 1.08E−07 A/cm2 to 8.92E−06 A/cm2. The corrosion mechanism changes from pitting corrosion to intergranular corrosion. The high-phase interfacial energy of the eutectic structure exacerbates the galvanic corrosion of the coatings.

Experimental and numerical simulation study of magnesium/aluminium dissimilar metal swing laser welding

In this study, AZ91/6061 joint were successfully prepared by using the swing laser welding process, and the process, microstructure, mechanical properties, and temperature field distribution of swing laser welding were investigated. During welding, the laser beam is always in the transverse swing state, which has a stirring effect on the liquid molten pool, optimizing the size and distribution of Mg-Al intermetallic compounds in the weld, forming mechanical interlocking structure, which is beneficial to reducing the hazardous effects of intermetallic compounds on the joint properties. The microstructure results show that the Mg/Al reaction interface mainly consists of (α-Mg+Al12Mg17) eutectic structure, and Al12Mg17, and the different compounds form a wave-shaped mechanical interlocking structure. Orthogonal test results show that the laser power has the greatest influence on the joint performance, when the laser power is 900 W, the shear strength of the joint is 40.72 MPa, the fracture occurs in the mechanical interlocking zone, and the fracture mode is brittle fracture. In this case, the strengthening mechanism is the mechanical interlocking structure that prevents crack extension and the stirring effect of the swing laser beam on the liquid molten pool that avoids the formation of continuously distributed bulk Mg-Al intermetallic compounds. Numerical simulation results show that the centre zone of the heat source moves from side to side with the swing of the laser beam, resulting in a more uniform temperature distribution in the joint.

Synergistic strengthening and toughening of eutectic CxCoCr3Fe5Ni high entropy alloy

CxCoCr3Fe5Ni (x=0, 0.1, 0.2 and 0.3, at.%) high entropy alloys (HEAs) were prepared via vacuum induction melting. The effects of carbon content on the microstructures and mechanical properties of the HEAs were intensively investigated. With the increase of the carbon content, the phase structure transforms from a dual-phase (FCC+BCC) to a eutectic mixture (FCC phase + M23C6 carbide). Compared to CoCr3Fe5Ni base alloy, the C0.2CoCr3Fe5Ni eutectic HEA exhibits a significantly improved yield strength (from 307.5 to 378.9 MPa), ultimate tensile strength (from 646.5 to 837.1 MPa), and ductility (from 55.4% to 56.1%). It is shown that these comprehensive enhancements of strength and ductility result from the effect of interstitial solid solution strengthening by carbon alloying and second phase strengthening via the eutectic structure.

Microstructure evolution and mechanical property of melt-grown Al2O3/GdAlO3/ZrO2 eutectic ceramics prepared by laser directed energy deposition

Highly dense Al2O3/GdAlO3/ZrO2 eutectic ceramics are one-step additively manufactured by laser directed energy deposition technique under different scanning speed to investigate the inherent response relationship between processing parameter, microstructure, and mechanical property. During the layer-wise deposition process, planar-cellular transition occurs near the bottom of the molten pool, leading to the transformation of irregular eutectic structure into eutectic colony structure lengthened along the building direction, accompanied by the refinement of microstructure dimension. With the increase of scanning speed, the eutectic spacing decreases, and the initially irregular “Chinese script” eutectic ultimately transforms into hexagonally arranged rod-like eutectic structure induced by lamellar instability. The rod spacing is 1.136 times larger than the lamellar spacing. The mechanical property of the laser 3D-printed Al2O3/GdAlO3/ZrO2 eutectic ceramic is manifested as isotropic. The hardness increases with the refinement of the microstructure, while the fracture toughness decreases as the eutectic morphology transforms into rod-like structure. The averaged hardness and fracture toughness are 16.27 GPa and 3.39 MPa‧m1/2, respectively.

Ternary eutectic growth and associated tensile properties of directionally solidified Al87Si11Ni2 alloy

The directional growth mechanism and associated tensile properties of ternary Al87Si11Ni2 eutectic alloy were investigated within a wide growth velocity range from 1 to 120 μm s−1 at a constant temperature gradient of 380 K cm−1. If eutectic growth velocity was below 40 μm s−1, this alloy exhibited a ternary lamellar eutectic structure composed of Si plates, Al3Ni chips and αAl matrix. As growth velocity increased to faster regime, the microstructure evolved into a complex structure characterized by primary αAl dendrites plus ternary eutectics. Correspondingly, the preferred crystalline orientation along solidification direction transformed from 101αAl //010Al3Ni // 101Si to 001αAl // 010Al3Ni //113Si. The tensile strength initially increased with the rise of growth velocity until 40 μm s−1, primarily due to the refinement of eutectic structure, and then decreased beyond this threshold, mainly resulting from the coarsening of primary αAl phase.

Evolution of Laves phase related to tensile properties in cast ATI 718Plus under pulsed electric current

The Laves phase will seriously deteriorate the subsequent hot working and welding performance of cast ATI 718Plus. In traditional homogenization annealing, two-stage treatment is used to prevent the formation of harmful eutectic structures due to the initial melting of the low-melting point Laves phase. This has several obvious disadvantages including high processing temperature, long processing time and complicated operation. Electrical pulsed treatment, as a new efficient, feasible and energy-saving green means, has rapidly achieved the dissolution of Laves phase. The increase in diffusion rate of Nb element in Ni matrix by pulsed electric current is due to the enhancement of defect migration and vacancy defect density, leading to a significant enhancement in the diffusion kinetics and accelerating the dissolution of Laves phase. Laves phase dissolution process under the pulsed electric current is from the aggregated state accompanied by dense needle like η phase to the discrete state accompanied by sparse needle like η phase, finally forming a single long strip and being dissolved into an intermittent state until it disappears. In all, using pulsed electric current instead of traditional heat treatment for annealing cast ingots has the potential to achieve one-step homogenization, completely dissolving the Laves phase while eliminating element segregation.

Effects of Hf and C on microstructure and mechanical properties of Re0.1HfxTa1.6W0.4(TaC)y refractory medium-entropy alloy

The trade-off between high-temperature strength and room-temperature ductility represents a critical concern for practical application of refractory high-entropy alloys (RHEAs). Here, a set of five Re0.1HfxTa1.6W0.4(TaC)y refractory medium-entropy alloys (RMEAs) were fabricated using the vacuum arc melting technique, and the effect of Hf and C on the microstructures and mechanical properties of these alloys was investigated. These RMEAs exhibit excellent high-temperature strength and favorable plasticity at room-temperature. The microstructures of the Re0.1HfxTa1.6W0.4(TaC)y alloys are hypoeutectic or eutectic structures, consisting of BCC solid solution and primary and secondary carbides. The carbides can be classified into two types: M2C and MC. Hf and C have an important influence on the grain size, carbide type and spatial configuration of the alloy, and in turn, influence the mechanical properties of the alloy. For instance, the content of MC-type carbides is proportional to the addition of Hf element, whereby a higher proportion of Hf results in reduced plasticity at room-temperature and enhanced softening resistance at elevated temperatures in the alloy. The carbides and BCC matrix exhibit synergistic strengthening behavior. The ultimate compressive strength of the five Re0.1HfxTa1.6W0.4(TaC)y alloys at 1450 °C is >950 MPa, while maintaining a fracture strain exceeding 11% at room-temperature. Notably, the Re0.1Hf0.1Ta1.6W0.4(TaC)0.25 alloy demonstrates a compressive strength of 1110 MPa at 1450 °C, which is 2.3 times greater than that of the NbMoTaW alloy at 1400 °C. Additionally, the fracture strain of the Re0.1Hf0.1Ta1.6W0.4(TaC)0.25 alloy at room-temperature is 16.9%, which is 8 times higher than that of the NbMoTaW alloy. The Re0.1HfxTa1.6W0.4(TaC)y alloy exhibit excellent mechanical properties at both room and high temperatures, making it a potential candidate for applications in fields that require high strength at ultra-high temperatures.

Development of prominent bonding strength in Al/Mg bimetal composites prepared by ultrasonic vibration-assisted compound casting: Effects of ultrasonic powers

In this work, the A356/AZ91D bimetal composites were prepared by ultrasonic vibration-assisted lost foam compound casting, and the effects of ultrasonic powers on interfacial microstructures and mechanical properties of the Al/Mg interfaces were investigated. Results revealed that the Al/Mg bimetal composites without ultrasonic vibration treatment (UVT) were heterogeneous, and the Al/Mg interface was composed of Al-Mg intermetallic compounds (IMCs, i.e., Al3Mg2 and Al12Mg17) area and Al-Mg eutectic structures (δ-Mg+Al12Mg17) area. The Mg2Si particles were gathered at the IMCs area and an oxide film that mainly composed of Al2O3 was existed between the IMCs area and eutectic structures area. With UVT, the oxide film was eliminated and the gathered Mg2Si particles were refined and dispersed by the acoustic cavitation effect, and part of the Al3Mg2 and Al-Mg eutectic structures were transformed into the Al12Mg17 due to the promoted solute interdiffusion, which improved the homogeneity of the Al/Mg interfaces. Besides, the grains of the Al/Mg interface with UVT under ultrasonic power of 75 W were significantly refined. The thickness of Al/Mg interface was increased with the increase of the ultrasonic power. Due to the excessive heat induced by UVT under the further increased ultrasonic power, the cooling rates and the degree of supercooling were reduced, resulting in the coarsening of interfacial grains. The microhardness of the Al/Mg interfaces was increased and got more uniform by UVT. The shear strengths of the Al/Mg bimetal composites with UVT were enhanced to 61.4 MPa from 32.4 MPa, with an increase of 89.5 % compared with that of the Al/Mg bimetal without UVT. This could be ascribed to the removal of the oxide film, the refinement of the interfacial grains and the dispersed and refined Mg2Si particles achieved by UVT, which hindered the crack propagation during deformation.

Effects of niobium and molybdenum addition on microstructural characteristics and wear properties of 14 wt%Cr white cast irons

White cast iron (WCIs) alloys were developed by adding Nb, Mo, and a combination of both (∼3 wt% Nb, ∼3 wt% Mo, ∼1 wt% Mo-2 wt% Nb) through melting and casting. The objective was to analyze the microstructural characteristics of the alloys, as well as the impact of reinforcing carbides on their mechanical and tribological properties. The alloy containing the highest percentage of niobium exhibited a refined microstructure, tending towards a eutectic structure, unlike the Mo-containing materials with totally hypoeutectic microstructures. The microstructural characteristics of the alloys and morphology of niobium carbides, as well as the percentage of M7C3 eutectic carbides produced were affected by the varying percentages of Nb and the Mo–Nb combination. Moreover, thermodynamic simulations revealed that the NbC carbide precipitated before the M7C3 eutectic carbides, austenite dendrites, and the MC (composed mainly of Nb containing bound Mo) carbide resulting from the Mo–Nb combination. The alloys containing Mo had similar bulk hardness values, while the alloy with the highest percentage of Nb showed a higher bulk hardness value. This was attributed to the effect of Nb on microstructure refinement and on the production of M7C3 eutectic carbides from the alloy. Although there were different reinforcing carbides (NbC, MC and M2C), the differences in microstructural characteristics had no noticeable influence on the Charpy impact energy. Micro-scale abrasive wear test (conducted with SiC abrasive slurry) demonstrated that the reinforcing carbides MC and mainly NbC had a beneficial effect in blocking and preventing the progression of continuous micro-cuttings and formation of grooves. The M7C3 and M2C carbides were less effective at protecting the matrix against the high-hardness SiC abrasive.

Repair feasibility and performance enhancement analysis of Fe-based alloy coating on ductile iron surface by high-speed laser cladding

In this paper, high-speed laser cladding technology with a scanning speed of 40 mm/s was used to clad the ductile iron surface with the Fe-based alloy coating. The coatings' microstructure, element distribution, crystallographic structure, wear resistance, and corrosion resistance were investigated by using an optical microscope, SEM, XRD, friction and wear testing machine, super depth-of-field microscope, and electrochemical workstation. The results show that the microstructure of the coating is mainly γ-Fe solid solution and carbide eutectic structure. The phases of the coating are FCC phase (γ-Fe dominated), BCC phase, and carbide. The elemental distribution of the coating cross-section elements is uniform, and no quality obvious defects such as large gas pores and cracks are found. The coating mass loss was 60.0% and 47.1% of the substrate for different friction parameters and the more significant coating oxide build-up phenomenon with increased loading force. The self-corrosion rate of the coating was 0.006 g/m2·h, and the substrate was 0.042 g/m2·h; the maximum impedance value of the coating (1.34×104 Ω·cm2) was increased 20 times based on the substrate (619.2 Ω·cm2). In summary, Fe-based coatings with these process parameters can repair failed ductile iron parts and significantly extend their service life.

Microstructure and thermoelectric properties of as-cast Ag2Te/AgBiTe2 and Ag2Te/Bi2Te3 two-phase alloys

The microstructure and thermoelectric properties of Ag2Te/AgBiTe2/Bi2Te3 eutectic alloys in the Ag-Bi-Te system were investigated in the present study. A self-consistent, thermodynamically optimized database of the Ag-Bi-Te system was developed to explain the microstructural features in the investigated alloys. Samples namely B0 (Bi2Te3 – 0 at.% Ag), B1 (Bi2Te3 – 5 at.% Ag), B2 (Bi2Te3 – 18.35 at.% Ag), B3 (Bi2Te3 – 28.35 at.% Ag), and B4 (Bi2Te3 – 38.35 at.% Ag) were synthesized by flame melting. Scanning electron micrographs of alloys reveal lamellar eutectic structures in which alloys B1 and B2 exhibit two distinct phases, consisting of β-Bi2Te3 and AgBiTe2, whereas alloys B3 and B4 display phase compositions corresponding to Ag2Te and AgBiTe2 phases. The X-ray diffraction reveals that the solidified alloys have hexagonal (AgBiTe2, Bi2Te3) and cubic β-Ag2Te crystal structures. The Scheil cooling calculations of these alloys using the developed thermodynamic database explain the microstructural features of the alloys. Furthermore, the mechanical characteristics of eutectic alloys B1 and B3 demonstrated improved hardness values, measuring 1.1 GPa and 1.2 GPa, respectively. Moreover, the transport characteristics show favourable attributes for thermoelectrics in high-temperature applications. It is important to highlight that all these alloys showcase transport properties that are highly advantageous for thermoelectrics. Notably, alloy B2 distinguishes itself with a remarkable ZT value of 0.42 at 540 K.

Manufacturing high-strength and corrosion-resistant 6063Al joints by an ultrasonic-assisted liquid and solid phase diffusion technology

High corrosion-resistance aluminum alloy joint obtained by filler metal containing Sn at relatively low temperatures is a longstanding goal for electronic products. In this research, 6063Al alloys was joined by a novel ultrasonic-assisted diffusion bonding via liquid phase and solid phase synergistic diffusion. It was performed via a hypereutectic interlayer of Zn-30Sn at 360 ℃ to joining 6063Al, obtaining a Zn-Al eutectoid structures joint. By the ultrasonic vibrating, the breaking of oxide film, the diffusing of liquid and solid state had been occurring in sequence during the joining process. It resulted in a series of diffusing phase transitions from “η-Zn phases + Sn-Zn eutectic structures” to “Zn-Al eutectoid structures + η-Zn phases”, and finally to “full Zn-Al eutectoid structures”, which were driven by the grain boundary penetration and chemical potential, respectively. The joints possessed a higher strength than the base metal. The joints with Zn-Al eutectoids have a better corrosion resistance that the tensile strength reduced 37.3% after a corroding of 72 h in 3.5 wt% NaCl solution in comparison with the soldered joints. Finally, the mechanism of ultrasonic accelerated diffusion, joint formation process and mechanism of improving corrosion resistance were discussed in detail.

Study on enhanced wear resistance of FeCoCrNi2MoSi high entropy alloy coatings induced by nano-layered eutectic and Laves phase

Wear is one of the primary challenges for high-temperature working components. In this paper, FeCoCrNi2MoSi eutectic high-entropy alloy coatings were successfully prepared by introducing MoNiSi ternary silicides with Laves structure into FeCoCrNi high-entropy alloys using laser cladding technology. The alloy achieves a balance of strength and toughness through the nanoscale eutectic structure with alternating FCC and Laves phases. Tribological experiments conducted over a wide temperature range from 25 °C to 800 °C show that the synergistic effect of the nano-lamellar structure and the alternating soft and hard structure makes the coating have excellent wear resistance at room temperature. The improvement of wear resistance at high temperatures (800 °C) is mainly due to the formation of the oxide film on the coatings.

Interfacial microstructure evolution and mechanical properties of FGH98 superalloy TLP joints with BNi-2 interlayer

FGH98 nickel-based powder metallurgy superalloy was successfully bonded via transient liquid phase (TLP) bonding technique with a BNi-2 interlayer. The typical joint consisted of three characteristic zones including: ASZ composed of multiple silicon borides, ISZ with uniform γ solid solution and dispersed small γ′ phases and DAZ containing multiple kinds of borides which exist within and at grain boundaries. With the increase of bonding temperature and holding time, ASZ was gradually replaced by the ISZ, and eutectic structure disappeared. But excessive temperature or time will cause grain coarsening, deteriorating the joint performance. Under the bonding parameters of 1130 °C −60 min, the joint with optimal shear strength was obtained, which is 882 MPa (94% of the base metal strength). The fracture occurs in the DAZ, which is a mixed fracture.

Effects of Chemical Composition and Solidification Rate on the Solidification Behavior of High-Cr White Irons

The effects of chemical composition and solidification rate on the solidification behavior of high-Cr white irons were investigated through directional solidification. Increasing the solidification rate in hypoeutectic alloys caused finer dendrite-arm spacing, as expected. The eutectic structure, which formed in the interdendritic region, was comprised of M7C3 and austenite; however, secondary dendrite arms of hypoeutectic alloys contained a few M7C3 particles that solidified prior to the eutectic structure. The transition from cellular to dendritic solidification occurred at a solidification rate between 50 µm/s and 100 µm/s in a near-eutectic alloy. In the near-eutectic alloy with cellular solidification, a directionally arrayed in-situ composite of M7C3/austenite formed within the cell. Speckle-like features appeared in the intercellular region due to M23C6 carbide precipitation during subsequent cooling after freezing. Like dendrite-arm spacing in hypoeutectic alloys, the inter-speckle spacing and the inter-fiber spacing became finer with an increasing solidification rate in the cellular solidification range.

Interfacial Polarization Locked Flexible β-Phase Glycine/Nb2CTx Piezoelectric Nanofibers.

Biomolecular piezoelectric materials show great potential in the field of wearable and implantable biomedical devices. Here, a self-assemble approach is developed to fabricating flexible β-glycine piezoelectric nanofibers with interfacial polarization locked aligned crystal domains induced by Nb2CTx nanosheets. Acted as an effective nucleating agent, Nb2CTx nanosheets can induce glycine to crystallize from edges toward flat surfaces on its 2D crystal plane and form a distinctive eutectic structure within the nanoconfined space. The interfacial polarization locking formed between O atom on glycine and Nb atom on Nb2CTx is essential to align the β-glycine crystal domains with (001) crystal plane intensity extremely improved. This β-phase glycine/Nb2CTx nanofibers (Gly-Nb2C-NFs) exhibit fabulous mechanical flexibility with Young's modulus of 10 MPa, and an enhanced piezoelectric coefficient of 5.0 pCN-1 or piezoelectric voltage coefficient of 129×10-3VmN-1. The interface polarization locking greatly improves the thermostability of β-glycine before melting (≈210°C). A piezoelectric sensor based on this Gly-Nb2C-NFs is used for micro-vibration sensing in vivo in mice and exhibits excellent sensing ability. This strategy provides an effective approach for the regular crystallization modulation for glycine crystals, opening a new avenue toward the design of piezoelectric biomolecular materials induced by 2D materials.

The influence of Gd content on the solidification and microstructure of AlSi7Mg0.3 casting alloy

The effects of Gd content on the solidification path and microstructure of an AlSi7Mg0.3 alloy have been studied. Two different Gd levels, 0.1 and 0.5 mass%, respectively, have been investigated while the material has been solidified at low (0.2 °C s−1) and high (1.3 °C s−1) cooling rates. Computer-aided thermal analysis and metallographic techniques have been used to study the solidification and microstructural evolution of the alloy at different Gd contents and cooling rates. The results show how Gd has no effect on the grain refinement at both cooling rates. The eutectic structure is unaffected at Gd level of 0.1 mass%. A concentration of 0.5 mass% Gd promotes the precipitation of the gadolinium phosphide (GdP) phase instead of aluminium phosphide (AlP) compounds, thus suppressing the eutectic plateau during the solidification and serving as nucleant for the GdAl2Si2 phase. The eutectic Si crystals solidified at low cooling rate are refined at 0.5 mass% Gd content, while the morphology of Si crystals is only partially modified at high cooling rate.

Corrosion behavior of erbium modified Zn-11Al-3Mg cast alloy in stagnant 3.5 wt% NaCl solution

Zn-11Al and Zn-11Al-3Mg-xEr (x=0, 0.05, 0.1, 0.5) alloys were prepared, and the microstructures and corrosion resistance of the alloys were investigated by scanning electron microscopy (SEM), x-ray diffraction (XRD), and electrochemical methods. The results show that the primary Al-rich phase in Zn-11Al alloys is corroded as the main anode. The electronegativity of the primary Al phase in Zn-11Al-3Mg alloys is higher than the primary MgZn2 phase, and the electronegativity of Al-rich and Mg2Zn11 phases is higher than that of the η-Zn phase in ternary eutectic structure. The primary Al-rich phase and Mg2Zn11 phases in the alloy are corroded as the main anodes. On the other hand, the erbium (Er) reacts with Al to form the AlEr phase, and the AlEr phase has a significant refining and homogenizing effect on the primary Al-rich phase in the Zn-11Al-3Mg alloy. When the content of Er is 0.05%, the primary Al phase transforms into fine discontinuous cellular structure. However, the increase of Er addition promotes the growth of primary Al-rich phase and the reduction of ternary eutectic, which weakens the corrosion resistance of the alloy.

Microstructure Features and Mechanical Properties of Casted CoFeB Alloy Target

CoFeB alloy, as a promising magneto-resistive material, has attracted extensive attention concerning the magnetic properties of its thin film in the field of magneto-resistive random memory (MRAM). Although there are many studies on the magnetic properties of CoFeB thin films, there is relatively little research on the microstructure and mechanical properties of casted CoFeB alloy. In this work, Co20Fe60B20 (at%) alloy was fabricated through the vacuum induction melting method, and its microstructure features and mechanical performance were studied. Scanning electron microscopy (SEM), electron back scatter diffraction (EBSD), and transmission electron microscopy (TEM) were utilized to characterize the microstructure, which consists of the coarse, needle-like Fe2B phase that crystallizes first, the primary lamellar binary eutectic structure (Fe2B + bcc-Fe), and the ternary eutectic structure (Fe3B + Fe2B + bcc-Fe phase). It is found that Fe3B precipitates on the Fe2B with a core–shell structure. The orientation of bcc-Fe is randomly distributed, while there are two main kinds of textures in Fe2B: {100} <001> and Gaussian texture {110} <001>. In terms of mechanical properties, Co20Fe60B20 alloy’s tensile strength is 140MPa, and the yield strength is 87MPa. Because the cracks are easy to generate and expand along the needle-shaped pre-crystallized Fe2B, the plasticity of Co20Fe60B20 alloy is very poor, only 1%.