Microstructure Transformation Research Articles

Modeling phase separation and composition patterning in FeCrAl alloys at neutron irradiation

Possible scenarios of the microstructural evolution of FeCrAl alloys under neutron irradiation are studied by using the phase-field method. The exploited approach is generalized by considering ballistic mixing of atoms, spatial rearrangement of point defects, and dynamics of their sinks (dislocation loops), self-consistently. Stability diagrams manifesting domains of main control parameters (irradiation temperature, damage rate, atomic relocation distance) governing precipitation are obtained. It is shown that depending on irradiation conditions a precipitation of the Cr-rich α′ -phase proceeds by either phase decomposition or composition patterning mechanism. Statistical analysis of precipitation kinetics is provided by studying precipitate number density, mean precipitate size and Chromium content in α′ -phase for a model alloy Fe-30%Cr-5%Al. A locality of point defects distribution with high concentration and dislocation loops growth are discussed. The hardening change is estimated for two possible scenarios of precipitation. Obtained results are verified with experimental observations. This study provides a deep insight into details of microstructural transformation in FeCrAl alloys during neutron irradiation.

Experimental study on effect of deformation temperature on mechanical and biological activities of Ti-6Al-7Nb titanium alloy

Titanium alloy plays a crucial role in biomedical applications, particularly in the field of medical implants. One of the most significant advantages of titanium alloy is its excellent biocompatibility. Eventhough, it offered excellent behaviour, at elevated temperature, titanium alloys may experience softening, which limits their application in environment with higher operating temperatures. In this investigation, hot tensile and biological behaviour of the Ti-6Al-7Nb under different operating temperatures (300 °C, 400 °C, 500 °C and 600 °C) is studied. The biological behaviour of the deformed Ti-6Al-7Nb titanium alloy treated with simulated body fluid is studied. The microstructure and phase transformation of deformed titanium alloy is evaluated using scanning electron microscope (SEM) and x-ray diffraction (XRD) respectively. It was revealed that at temperature of 600 °C, the mobility of molecules at the interface between the solid and liquid phases increases. This enhanced mobility can lead to better wetting of the solid surface by the liquid, resulting in a decrease in the contact angle. The elevated temperature facilitates improved grain development, recrystallization and mobility. The coarser grains could result from deformation at temperature higher than 600 °C. It was concluded that the Ti-6Al-7Nb titanium alloy deformed with 600 °C showed the improvement in contact angle of 42 ± 2° and biocompatibility.

Microstructure and Phase Transformation Behavior of NiTiCu Shape Memory Alloys Produced Using Twin-Wire Arc Additive Manufacturing

NiTiCu thin walls were produced by twin-wire arc additive manufacturing (T-WAAM) using commercial NiTi and Cu wires as the feedstock materials. This approach aims to solve the problems typically associated with large phase transformation hysteresis in NiTi shape memory alloys. The microstructure, mechanical properties, and phase transformation behavior of the as-deposited NiTiCu alloy were comprehensively examined. The results revealed that the as-deposited NiTiCu alloy was well-formed, with its microstructure showed columnar, equiaxed, and needle-like grains, depending on the location within the deposited walls. The microhardness gradually increased from the first to the third layer. The Cu content was 20.80 at%, and Cu-based precipitates were formed in the as-deposited NiTiCu. The volume fractions and lattice parameters of the matrix and precipitates in the as-deposited NiTiCu material were analyzed using high-energy synchrotron X-ray diffraction. The martensitic phase was identified as a B19 crystal structure, and the as-deposited NiTiCu underwent a one-step B2-B19 phase transformation. The tensile strength and fracture strain were approximately 232 MPa and 3.72%, respectively. In particular, the addition of Cu narrowed the phase transformation hysteresis of the as-deposited NiTiCu alloy from 24.4 to 7.1 ℃ compared with conventional binary NiTi alloys. This study expands the potential of T-WAAM in modifying the phase transformation behavior of NiTi-based ternary alloys.

Influence of high-strain-rate compression and subsequent heat treatment on (TiNbZr)89(AlTa)11 refractory high-entropy alloys: Dynamic-mechanical behavior and microstructural changes

This study explored the dynamic-mechanical behavior of a novel low-density (TiNbZr)89(AlTa)11 refractory high-entropy alloy (RHEA) across strain rates ranging from 1.0 × 103 to 3.5 × 103 s−1. A significant increase in the yield and ultimate compressive strengths with rising strain rates up to 3.0 × 103 s−1 was observed and attributed to enhanced dislocation activities and stress-induced microstructural transformations. The formation of the B2 phase and Zr5Al3 precipitates was found to be crucial in bolstering the alloy strength at high strain rates. Beyond strain rates of 3.0 × 103 s−1, a decrease in strength occurred due to thermal softening and strain localization. Microstructural analyses at 3.5 × 103 s−1 revealed grain refinement, the development of micro shear bands, and dislocation tangles, which were indicative of dynamic recrystallization. Besides, the findings also revealed that the post-dynamic compression heat treatment further enhanced the hardness and microstructural stability of the alloy. These results highlight the potential of the (TiNbZr)89(AlTa)11 RHEA for applications requiring materials with high strength-to-weight ratios, particularly in dynamically loaded environments. It is expected that the results of this study will further advance our fundamental understanding of the behavior of RHEAs under extreme conditions, thereby opening new avenues for material innovation.

Microstructural Evolution and Phase Transformation on Sn–Ag Solder Alloys under High‐Temperature Conditions Focusing on Ag3Sn Phase

This study investigates the microstructural and phase transformations in Sn–Ag solder alloys under high‐temperature conditions, utilizing X‐ray diffraction, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) analyses. Analytical techniques are employed pre‐ and postcontrolled thermal cycling from 30 to 180 °C, aimed at emulating solder reflow processes. The analysis at room temperature demonstrates pronounced crystalline peaks, suggesting a preferred orientation within the crystal structure. Upon heating, peak broadening suggests grain growth and the onset of recrystallization. SEM and energy‐dispersive spectroscopy analyses corroborate these findings, displaying a fine‐grained, well‐distributed microstructure with a homogenous composition of Sn and Ag elements. EBSD provides insights into the orientation and texture of grains, revealing a weak‐to‐moderate texture across the phases. Postexperiment data indicate a dominant presence of larger grains and significant variation in grain size, with an area‐weighted mean grain size of 68.47 μm and a standard deviation of 8.68 μm; this suggests significant grain growth and coarsening of the Ag3Sn intermetallic compounds. These structural evolutions have crucial implications for the mechanical properties and reliability of the solder alloy in electronic assemblies, underscoring the need for further exploration of lead‐free solder materials in the electronics industry.

Gelatinization and fermentation synergy: investigating the protein digestibility, mineral bioaccessibility and microstructural transformations of black mash beans through Saccharomyces cerevisiae and Lactobacillus spp

ABSTRACT This study explored the nutritional qualities of black mash bean flour impacted by fermentation, gelatinization and their combination. Protease activity, in vitro protein digestibility (IVPD), and protein solubility were evaluated for both fermented and unfermented black mash bean flour samples. Interestingly, when compared to fermented samples and gelatinized mash bean flour (GMBF), raw mash bean flour (RMBF) showed the highest protein solubility. Due to enzymatic activity and protein hydrolysis, fermentation with Lactobacillus E14 and Saccharomyces cerevisiae MK-157 enhanced protein solubility. Prolonged fermentation timeframes were positively correlated with protease activity and IVPD, suggesting the degradation of complex proteins. The highest levels of IVPD (90.12%) and protease activity (5546.78 U/g) were detected in GMBF fermented by S. cerevisiae MK-157, indicating the impact of fermentation on protein breakdown. The Lactobacillus E14-fermented RMBF exhibited 5521.45 U/g of protease activity and 87.54% IVPD. The mineral content of the fermented samples was substantially greater than that of the unfermented GMBF. The increased calcium, magnesium, potassium, sodium, iron, zinc, and copper levels for the GMBF fermented by S. cerevisiae MK-157 indicated that fermentation facilitated the release of minerals from chelated compounds. Microscopic examination revealed higher protein quantities in the fermented flour as well as hydrolyzed and broken starch granules embedded in the protein matrix. Large mash bean proteins were shown to be proteolyzed during fermentation into smaller peptides by SDS PAGE. Storage proteins were extensively broken down during fermentation with S. cerevisiae MK-157, whereas Lactobacillus E14 displayed a more focused pattern of hydrolysis. The nutritional profile of black mash bean flour was improved by fermentation with Lactobacillus E14 and S. cerevisiae MK-157.

Transient gas-induced differential refractive index effects in as-drawn hollow core optical fibers

When a hollow core fiber is drawn, the core and cladding holes within the internal cane geometry are pressurized with an inert gas to enable precise control over the internal microstructure of the fiber and counteract surface tension forces. Primarily by considering the temperature drop as the fiber passes through the furnace and the geometrical transformation of the internal microstructure from preform-to-fiber, we recently established that the gas pressure within the final ‘as-drawn’ fiber is substantially below atmospheric pressure. We have also established that slight changes in the gas refractive index within the core and surrounding cladding holes induced by changes in gas pressure are sufficient to significantly affect both the modality and loss of the fiber. Here we demonstrate, through both simulations and experimental measurements, that the combination of these effects leads to transient changes in the fiber’s attenuation when the fibers are opened to atmosphere post-fabrication. It is important to account for this phenomenon for accurate fiber characterization, particularly when long lengths of fiber are drawn where it could take many weeks for every part of the internal microstructure to reach atmospheric pressure.

Effect of Mo and Cr on the Microstructure and Properties of Low-Alloy Wear-Resistant Steels.

Low-alloy wear-resistant steel often requires the addition of trace alloy elements to enhance its performance while also considering the cost-effectiveness of production. In order to comparatively analyze the strengthening mechanisms of Mo and Cr elements and further explore economically feasible production processes, we designed two types of low-alloy wear-resistant steels, based on C-Mn series wear-resistant steels, with individually added Mo and Cr elements, comparing and investigating the roles of the alloying elements Mo and Cr in low-alloy wear-resistant steels. Utilizing JMatPro software to calculate Continuous Cooling Transformation (CCT) curves, conducting thermal simulation quenching experiments using a Gleeble-3800 thermal simulator, and employing equipment such as a metallographic microscope, transmission electron microscope, and tensile testing machine, this study comparatively investigated the influence of Mo and Cr on the microstructural transformation and mechanical properties of low-alloy wear-resistant steels under different cooling rates. The results indicate that the addition of the Mo element in low-alloy wear-resistant steel can effectively suppress the transformation of ferrite and pearlite, reduce the martensitic transformation temperature, and lower the critical cooling rate for complete martensitic transformation, thereby promoting martensitic transformation. Adding Cr elements can reduce the austenite transformation zone, decrease the rate of austenite formation, and promote the occurrence of low-temperature phase transformation. Additionally, Mo has a better effect on improving the toughness of low-temperature impact, and Cr has a more significant improvement in strength and hardness. The critical cooling rates of C-Mn-Mo steel and C-Mn-Cr steel for complete martensitic transition are 13 °C/s and 24 °C/s, respectively. With the increase in the cooling rate, the martensitic tissues of the two experimental steels gradually refined, and the characteristics of the slats gradually appeared. In comparison, the C-Mn-Mo steel displays a higher dislocation density, accompanied by dislocation entanglement phenomena, and contains a small amount of residual austenite, while granular ε-carbides are clearly precipitated in the C-Mn-Cr steel. The C-Mn-Mo steel achieves its best performance at a cooling rate of 25 °C/s, whereas the C-Mn-Cr steel only needs to increase the cooling rate to 35 °C/s to attain a similar comprehensive performance to the C-Mn-Mo steel.

Compositionally graded titanium to aluminum processed by laser powder bed fusion process: Microstructure evolution and mechanical properties

A compositionally graded Ti–Al alloy with a designed composition range from pure Ti to pure Al was successfully produced by a laser powder bed fusion (L-PBF) system equipped with two powder feeders. The compositionally graded Ti–Al profile is confirmed by scanning electron microscopy, X-ray diffraction analysis, electron backscatter diffraction microscopy, and transmission microscopy. The graded material is free of macro-horizontal cracks, but micro-cracks appear at the center of the sample. Varying the Ti and Al ratio along the build direction induces microstructural changes, transforming α+β-Ti into solid solution, creating intermetallics (Ti and Al), and yielding an Al phase with diverse morphologies. Additionally, the Ti–Al ratio's influence on microstructure formation and phase evolution results in varying mechanical properties among the graded material's layers. The results demonstrate that the L-PBF process can achieve continuous compositional grading of Ti–Al materials in a single run. Moreover, this study hold the potential to facilitate the design and production of numerous compositional variants for high entropy alloys and multi-materials, enabling future investigation into microstructural evolution, phase transformation, and physical and mechanical properties.

A fully-coupled FEM-based 2D metallo-thermo-mechanical model of laser-assisted machining of Ti-6Al-4V - a focus on residual stresses

The complex interaction between the laser beam, the workpiece, and the cutting tool during laser-assisted machining (LAM) can result in considerable thermal gradients, variational strains and microstructural phase transformations, ultimately leading to residual stresses. This study presents a finite element-based model for the LAM of Ti-6Al-4V alloy, integrating the material’s metallurgical transformations and thermo-mechanical behaviour to predict residual stresses. The thermal, mechanical, and metallurgical aspects of the LAM process are fully-coupled in the model, accurately capturing chip formation and serration, while also accommodating strains induced by metallurgical transformations. Implemented within the finite element software, ABAQUS, the model’s predictions for surface residual stresses align closely (¿90%) with experimental data from literature. Notably, the model elucidates the transition of surface residual stresses towards tensile nature due to laser heating in LAM. The results reveal that the metallurgical transformation exerts a more pronounced influence at lower cutting speeds. Moreover, surface residual stresses tend towards tensile nature with increased laser power but shift towards compressive nature with higher laser-tool gap, cutting speed, and feed. Depth-wise residual stress distributions underscore the significant impact of laser power, speed, and feed compared to laser-tool gap. The proposed model can be used to optimise the LAM process and improve the quality and reliability of the finished products.

Designing the heat treatment process for Mg-10Gd-4Y-xZn-0.6Zr (wt.%) alloy: A study on the transformation of microstructure and properties

Heat treatment of Mg10Gd-4Y-xZn-0.6Zr (x = 0, 1, 2 wt%) alloys has been optimized based on thermodynamic calculations and experiments. The phase transformations during the heat treatment and their effect on the mechanical properties of the alloys were discussed. Using thermodynamic calculations, three solution treatment temperatures of 475 °C, 500 °C, and 525 °C were determined, and the phase transformation under these temperatures were calculated and characterized, the results aligned well with experimental results. The optimal solution treatment technology was determined to be 500 °C for 18 h. After solution treatment, experimental alloys were subject to isothermal aging at 225 °C, the peak aging time for the experimental alloys was established. The microstructure under peak-aged state of the alloy was characterized, revealing a co-existed β’ and β1 phases. The GWZ1041K alloy, after peak aging treatment, exhibited optimal mechanical properties, with a tensile strength, yield strength, and elongation of 392.3 MPa, 249.3 MPa, and 5.7%, respectively. The study further analyzed the reasons for the microstructure transformation during the heat treatment and their influence on mechanical properties.

Microstructure and texture transformation of wedge-shaped rolled 3%Y2O3p/ZGK200 composites

The microstructure and texture transformation of 3%Y2O3p/ZGK200 composites after wedge-shaped rolling were investigated. The 3%Y2O3p/ZGK200 composites could be wedge-shaped rolled for 50 % reduction without obvious edge cracks. Basal <a> slip, prismatic <a> slip and pyramidal <c+a> slip detected by in-grain misorientation axes (IGMA) combined with Schmid factor (SF) analysis were abundantly activated during the whole rolling process. Different from the activation of all kinds of dislocation slips, many {10 1‾ 2} extension twins and few {101‾ 1}-{101‾ 2} secondary twins were activated with a reduction of 10 %. With increasing reduction from 30 % to 50 %, {101‾ 1}-{101‾ 2} secondary twins and {101‾ 1} compression twins started to play more important roles. Finally, the rolled deformed grains were elongated along rolling direction (RD) with abundant twins. During the whole rolling process, few recrystallized grains were found in the composites due to the effect of Gd addition. The {101‾ 2} extension twins whose c-axis oriented along normal direction (ND) should be attributed to the formation of basal texture, which was kept unchanged during the whole rolling process.

Mechanical behavior of dissimilar AL6XN-IN718 welded joint obtained by cold metal transfer

Cold metal transfer (CMT) welding process was used to join the AL6XN super-austenitic stainless steel to a nickel-based super alloy IN718. Microhardness, tensile and low cycle fatigue tests were carried out to determine the mechanical properties of the welded joint. The heat used to perform the weld decreases the microhardness in the heat affected zone (HAZ) of the IN718 material. A decrement of about 50% with respect to the base material (∼410 HV0.2) was observed, which is attributed to the microstructural transformation produced by the weld thermal cycles, inducing the partial dissolution of the γ'′ phase in the nickel matrix. In contrast, the HAZ on the AL6XN side, the microhardness tends to be similar with respect to the base material (∼203 HV0.2). In terms of the fracture energy, determined from the stress-strain plot, the welded joint decreases about 60–65% with respect to the base materials. This tendency was also observed in the case of the Charpy impact test behavior. From the low cycle fatigue test, it was observed that AL6XN material and AL6XN-IN718, performed better than the IN718 alloy, i.e. more tolerance to the strain cyclic, increasing the number of cycles to failure. A 3-D transient thermal conduction finite element model was developed to correlate the thermal history with the microstructural transformation on the HAZ and mechanical properties. The weld thermal cycles are in good agreement with the experimental measurements obtained by K-type thermocouples.

Multi-sensor-based process monitoring and quality assessment during laser forming of novel titanium foam to prevent cellular structure damage

Titanium foam finds its application in different fields like battery electrodes, heat exchangers, biological prosthetics, and lightweight structures for aeronautical parts. However, the inherent property of the foam to fail during mechanical loading conditions poses a challenge in providing final shape to these materials for practical applications. The present work investigates forming of Titanium foam (Ti Foam) using inline process monitoring for achieving controlled foam deformation while maintaining its quality without failure. Infrared (IR) pyrometer and laser-based displacement sensor were used to monitor the foam deformation behavior and thermal signature. The monitoring data were used to understand the process mechanism of laser forming. The bending mechanism within the foam was analysed with respect to solid sheet bending process. The correlation of the achieved bending angles, was attempted with the process parameters for surface, microstructural, elemental, and phase transformation. A critical analysis of Ti foam behavior, like surface melting, in situ oxidation, phase transformation, and formation of nano-structures on foam surface was addressed based on process parameter combinations. Micro-computed tomography (μCT) was carried out to investigate the pore deformation mechanism. Metallurgical characterisations for foam surface and phase analysis were carried out using X-ray photoelectron spectroscopy (XPS) and tunneling electron microscopy (TEM) to determine the chemical and crystallographic states of the laser-formed surface.

Advancements and Challenges in Linear Friction Welding of Inconel 718: A Comprehensive Review

This comprehensive review explores the linear friction welding of Inconel 718, a super alloy widely employed in aerospace and other high-temperature applications. Delving into the intricate relationship between process parameters and material properties, the paper examines microstructural transformations and their impact on mechanical integrity. Discussions encompass weldability, common defects, and mitigation strategies, providing valuable insights for practitioners. The review also highlights the evolving landscape of research trends, recent developments, and real-world applications, showcasing the versatility of linear friction welding. Challenges in the process are analyzed, offering a nuanced perspective on current limitations and avenues for improvement. Through a comparative lens with traditional welding techniques, the paper elucidates the unique advantages of linear friction welding in enhancing efficiency and performance. This synthesis of knowledge contributes to a holistic understanding of the state-of-the-art in linear friction welding of Inconel 718, presenting opportunities for future advancements in this critical domain.

Single-pass high-power laser-Arc hybrid welding of thick stainless steel clad plates: Microstructure and mechanical properties

In order to solve the existing problem of low efficiency of multi-layer and multi-pass welding methods for thick stainless steel clad plate (SSCP), this paper proposes high-power laser-arc hybrid welding (HP-LAHW) single-pass weld thick SSCP. The effects of wire feeding rate (WFR) on the weld's composition distribution, microstructure and mechanical properties were investigated. The weld morphology is nail-shaped, consisting of a wide arc zone (ArcZ) within the stainless steel layer and a long narrow laser zone (LaserZ), mainly in the carbon steel layer. With the increase of WFR, the dilution rate of the carbon steel layer to the ArcZ decreases first and then increases. The influence of WFR on the microstructure and mechanical properties of the weld is observed mainly in the ArcZ. When the WFR reaches 6 m/min, the composition of the microstructure within the ArcZ will change from martensite, ferrite, and a small amount of granular austenite to ferrite and a small amount of austenite, resulting in the microhardness of the ArcZ decreasing rapidly from 398 HV to 210 HV. The solidification type and microstructure transformation mechanisms within the weld were elucidated based on quantitative calculations of the chromium and nickel equivalent ratios. The microstructure of the LaserZ in all welds is predominantly martensitic due to the rapid cooling rate, which makes the tensile properties of the weld higher than the base metal (BM). The results of this study provide technical support for realizing high-efficiency and high-performance single-pass HP-LAHW of thick SSCP.

Effect of graphene addition on microstructure and wear behaviour of the A356-based composite fabricated by thixoforming process

Employing graphene as reinforcement in an aluminium matrix is a viable approach for developing composites with exceptional mechanical properties and wear resistance owing to its two-dimensional structure and high strengthening efficiency. This study aims to investigate the microstructure and wear behaviour of A356 aluminium matrix composites reinforced with different graphene nanoplatelets (GNPs) amounts (0.3, 0.5 and 1.0 wt%). The feedstock of composites underwent stir casting before being subjected to the thixoforming process. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy micrographs (TEM) demonstrated the microstructure transformation of the composites after fabrication and the presence of carbon elements in the A356 matrix composite, respectively. TEM micrographs also displayed the existence of aluminium carbide (Al4C3) compound in the composites due to the reaction of aluminium matrix and graphene during fabrication. The hardness testing results revealed the hardness of the composite with 0.3 wt% GNPs is higher than that of A356 alloy by showing an improvement of 51.4% after the thixoforming process. The wear resistance of the composites was enhanced by decreasing the wear rate. In comparison with the as-cast and thixoformed A356 alloys, the thixoformed composite reinforced with 0.3 wt% GNPs exhibited the lowest wear rate, demonstrating a reduction of 18.7% and 11.5%, respectively. These findings demonstrated the significance of GNPs as an effective self-lubricating and favourable reinforcement for A356 aluminium matrix composite in the automotive industry.

Remediation effectiveness of aging diesel-contaminated soil using thermochemical treatment: Soil microstructure transformation and reusability

This study investigated the microstructure transformation observed in an aging diesel-contaminated soil after thermochemical treatment (DT150°C + PS) to explore its impact on engineering reusability. Three thermal remediation procedures (i.e., DT150°C, DT350°C, and DT550°C) were selected as the control group. The results show that: (a) Pyrolytic carbon was produced in the DT350°C and DT550°C, while none was produced in DT150°C and DT150°C + PS; (b) Iron-based minerals and organic matter in DT150°C + PS, DT350°C, and DT550°C were combusted and decomposed to release the Fe(II) substances; under stronger oxidation environments, Fe(II) substances would further transform into more stable Fe(Ⅲ) substances; and (c) Halloysites and illites were formed in DT350°C, palygorskites and cordierites were formed in DT550°C, and oxidation in DT150°C + PS produced the sulfate minerals. The formed sulfate minerals in the DT150°C + PS sample filled pores and provided the skeleton strength, resulting in high unconfined compressive strength and poor permeability. Using a self-developed assessment model, only the DT150°C + PS sample showed an improvement (calculated as 2.96 × 10−5) in engineering performance and other methods led to the deterioration of soil mechanical properties. Thermochemical treatment is more suitable for engineering reuse, and this study can provide a theoretical basis for evaluating the greener reusability of contaminated soil after thermal or thermochemical remediation.

Analysis of Microstructural Transformations Induced by Thermal Aging of Co-Cr-Ni-W-C Alloy Deposits and Their Impact on Corrosion Behavior in a 3.5% NaCl Medium

Analysis of Microstructural Transformations Induced by Thermal Aging of Co-Cr-Ni-W-C Alloy Deposits and Their Impact on Corrosion Behavior in a 3.5% NaCl Medium

Phase transformation of AB5 to AB2 type phase on substitution of Mn with Zr in TiVCoNi (ZrxMn2-x) (x = 0, 0.3, 0.6, 1.0) high entropy alloys

In this present investigation, we discussed the synthesis, microstructure, and phase transformation from BCC (AB5) to C14 Laves (AB2) phase in TiVCoNi (ZrxMn2-x) (x = 0, 0.3, 0.6, 1.0) high entropy alloys on substituting Mn with Zr. These high entropy alloys were synthesized using a 35 kW radio frequency induction furnace under an argon atmosphere. At x = 0 (i.e. in quinary HEA), the single BCC phase was observed, whereas at x = 1 (i.e. in hexanery HEA), the single C14 Laves phase was found to be stable. The calculations of the thermodynamic parameters were done with the help of Miedema's semi-empirical model and other models available in the literature. TiVCoNi (ZrxMn2-x) high entropy alloys exhibited mixing enthalpy at x = 0, 0.3, 0.6, 1 as −15.6 kJ/mol, −18.1 kJ/mol, −22.8 kJ/mol, −25.3 kJ/mol respectively. The corresponding atomic size mismatch was found to be 10.03%, 11.85%, 10.18%, and 9.86%. It is established that on replacing Mn with Zr, the mixture of the BCC and Laves phase was observed, which was converted into a single C14 intermetallic Laves phase at equiatomic composition, i.e., x = 1. Further, the study of surface morphology and elemental composition of these as-cast high entropy alloys gives us the idea that hardness increases on substitution of Mn in BCC (at x=0) phased-based; TiVCoNi (ZrxMn2-x) (x = 0, 0.3, 0.6, 1.0) high entropy alloys due to the evolution of harder C14 Laves phase.