Deep Dimples Research Articles

Effect of Trace Rare Earth Element Cerium (Ce) on Microstructure and Mechanical Properties of High Strength Marine Engineering Steel

In this paper, FH460 special steel with rare earth element cerium (Ce) was selected, and the control group without Ce was set up. By changing the content of Ce, the microstructure, phase transition point, and mechanical properties of the test steel were observed to study the effect of trace rare earth element Ce on the microstructure and mechanical properties of high-strength marine engineering steel. The morphology and energy spectrum of inclusions in three kinds of test steels were observed by SEM, and the morphological changes in inclusions in FH460 high-strength marine engineering steel after adding Ce were investigated. The fracture morphology and energy spectrum analysis were carried out by combining the tensile test at room temperature and the gradient low temperature impact toughness test, and the effect of trace Ce on the mechanical properties of the test steel was comprehensively analyzed. The results show that the addition of Ce changes the phase transformation temperature of Ac1 and Ac3, and refines the original microstructure of the test steel. SEM observation showed that the addition of Ce changed the long strip MnS and polygonal irregular Al2O3 inclusions into ellipsoids, which reduced the size of inclusions. The gradient low temperature impact test shows that with the decrease in temperature, the fracture dimple depth of the three test sheets of steel decreases, and the Ce-containing test steel forms a deep dimple centered on rare earth inclusions, which hinders the crack propagation and significantly improves the low temperature impact toughness of the test steel.

Heat transfer enhancement and pressure drop performance of Al2O3 nanofluid in a laminar flow tube with deep dimples under constant heat flux: An experimental approach

This study examines the heat transfer enhancement and pressure drop of Al2O3 nanofluid in deep dimpled tubes in both longitudinal and circumferential directions. It explores mechanisms that improve the thermal performance of this novel tube geometry. Experiments were conducted using plain and deep dimpled tubes under laminar flow with Reynolds numbers from 500 to 2250, a constant heat flux of 10,000 W/m2, and nanofluid concentrations from 0.1 wt% to 1 wt%. The findings indicate that local velocity enhancement, vortex generation, and flow rotation and mixing are the three main mechanisms that improve the thermal performance of deep dimpled tubes. The results demonstrate that a deep dimpled tube with 1 wt% nanofluid can increase the convective heat transfer coefficient by up to 3.42 times compared to a smooth tube at Re = 2250. At this Reynolds number, the Nusselt number reaches a maximum of 41.80, and the friction factor ratio increases by only 1.82. Additionally, circumferential analysis reveals how dimple-induced vortices enhance heat transfer. The results also indicate that the tube geometry modification changes the flow regime zones, allowing turbulent flow at lower Reynolds numbers near Re = 2000, as identified by Nusselt number and friction factor plots. The deep dimpled tube has a low improvement penalty, with the highest friction factor of 0.38 at Re = 500 and high thermal enhancement, resulting in a performance evaluation criterion (PEC) of up to 2.80 in the studied region. However, the deep dimpled tube is unsuitable for Reynolds numbers below 1000. For higher velocities, replacing simple tubes with deep dimpled tubes in traditional heat exchangers is highly recommended.

On the use of thermomechanical processing to enhance the strength-ductility-toughness balance of plain low-carbon steel

This study aimed to fabricate a dual-phase (DP) steel with a combination of high strength-ductility-toughness by thermomechanical processing for industrial applications. Accordingly, the effects of 40 % cold deformation and intercritical annealing temperature on the microstructural evolution and tensile properties of low-carbon steel were studied. The microstructure of dual-phase steels consisted of ferrite (α) and martensite (α'), however, the morphology of martensite was different. With increasing the intercritical annealing temperature, the martensite fraction increased gradually from 0.41 at 770 °C to 0.51 at 860 °C. Also, the increase of martensite fraction from 0.41 to 0.51 caused a decrease in the martensite carbon concentration from 0.174 to 0.142 wt%. All dual-phase steels had a larger hardness than the as-received steel. When the temperature of annealing increased from 770 °C to 860 °C, the yield strength enhanced from 370.4 to 496.3 MPa, the ultimate tensile strength improved from 642.0 to 809.2 MPa, the total elongation decreased slightly from 31.8 % to 29.8 %, and the energy absorption increased from 190.0 to 217.6 J/cm3. The work hardening rate of all DP samples was considerably higher than other samples. Unlike initial, quenched, and rolled samples, the DP steels exhibited three-stage strain hardening behavior with increasing the true strain. For all dual-phase steels, a perfect ductile fracture was observed, with numerous uniform deep and coarse dimples. The dominant mechanism in the fabricated dual-phase steels was interface decohesion.

The influence of various welding wires on microstructure, and mechanical characteristics of AA7075 Al-alloy welded by TIG process

Owing to their exceptional mechanical properties, the various welding wires used to combine aluminum can meet the needs of many engineering applications that call for components with both good mechanical and lightweight capabilities. This study aims to produce high-quality welds made of AA7075 aluminum alloy using the GTAW technique and various welding wires, such as ER5356, ER4043, and ER4047. The microstructure, macrohardness, and other mechanical characteristics, such as tensile strength and impact toughness, were analyzed experimentally. To check the fracture surface of the AA7075 welded joints, the specimens were examined using optical and scanning electron microscopy (SEM). A close examination of the samples that were welded with ER5356 welding wire revealed a fine grain in the weld zone (WZ). In addition, the WZ of the ER4043 and ER4047 welded samples had a coarse grain structure. Because the hardness values of the welded samples were lower in the WZ than in the base metal (BM) and heat-affected zone (HAZ), the joints filled with ER5356 welding wire provided the highest hardness values compared to other filler metals. Additionally, the ER4047 filler metal yielded the lowest hardness in the weld zone. The welding wire of ER5356 produced the greatest results for ultimate tensile stress, yield stress, welding efficiency, and strain-hardening capacity (Hc), whereas the filler metal of ER4043 produced the highest percentage of elongation. In addition, the ER4047 fracture surface morphology revealed coarser and deeper dimples than the ER5356 fine dimples in the welded joints. Finally, the highest impact toughness was obtained at joints filled with the ER4047 filler metal, whereas the lowest impact toughness was obtained at the BM.

Investigating the microstructure and mechanical properties of Al–Ag-Sc ultra-fine grain alloy processed by accumulative rolling bonding method

The aim of the present study is to investigate the effect of accumulative roll bonding (ARB) and precipitation hardening on the microstructure development and there of mechanical properties of ultrafine grained Al–Ag-Sc alloy. For this purpose, the samples were heated to a temperature of 600 °C for 24 h, and then they were quenched in water. In order to carry out the two-stage precipitation hardening process, the samples were placed in the furnace at a temperature of 350 °C for 5000 s in the first stage, which was followed by quenching in water. In the second stage, they were heated to 250 °C for 5000 s following by water quenching too. Following, the samples were subjected to the ARB for up to 8 cycles. Scanning Electron Microscope (SEM) equipped with Electron Backscatter Diffraction (EBSD) and energy dispersive spectroscopy (EDS) techniques, and X-Ray Diffraction (XRD) was used to verify the microstructure and phase analysis of the prepared samples. Also, tensile and microhardness tests were conducted to confirm the mechanical properties, and pin-on-disk tests were done to check wear behavior. Microstructural parameters such as crystallite size, microstrain, and density of dislocations in rolled sheets were estimated using the Rietveld method. The Results have shown that applying various cycles of the ARB process leads to the development of ultra/nano grain structure. In that sense, performing 8-cycle of the ARB transformed the low angle grain boundaries (LAGBs) of the 4-cycle ARB condition to high angle grain boundaries (HAGBs). Results showed that there is proper welding between different layers, except for the layers created in the last cycle. Similarly, the obtained size of the crystallites demonstrates that the samples become finer when ARB cycles are increased. The results of the mechanical tests indicated that after 8 cycles, there is approximately 3.5-fold and 2.5-fold increase in the tensile strength and hardness compared to the original (annealed) sample, respectively. While the elongation decreased slowly and reached 1.5% in the 8th cycle. A fractography of the fracture surface of the original sample included deep and coaxial dimples, indicating a ductile fracture. Analysis of wear surface degradation showed that scratch wear occurred for all samples.

Effect of content on microstructure, oil painting pigment, and tensile properties of laminar composites

In this research, the Cu/Al-Al2O3 laminar composites were manufactured by pressureless infiltration casting and roll bonding processes. The effect of alumina content on microstructure, tensile properties and oil painting pigment was studied. The SEM images showed that the whiskers were aligned along rolling direction. By increasing the alumina content, the interfaces between Cu and Al-Al2O3 became wavier. The increase of whiskers improved the yield and ultimate strengths while reduced the elongation. Also, the fracture surfaces of composites indicated smaller dimples in composites with high whiskers’ content. Deeper dimples appeared near whisker cluster due to the debonding between Al and Al2O3. By increasing alumina content, the composites also experienced more oil painting penetration as a result of porosities near whiskers.

The effect of ratcheting strain on post-ratcheting tensile test of metal matrix composites (MMCs) reinforced by Fe3O4 nanoparticles manufactured by the accumulative roll bonding (ARB) process

This article concerns the effect of strain accumulation during low-cycle fatigue on the post-fatigue tensile behavior of metal matrix composites (MMCs) with identical layers of aluminum reinforced by Fe3O4 nanoparticles produced via the accumulative roll bonding (ARB) technique. Work-hardening behavior, deduced from ratcheting curves, was evaluated by the post-fatigue tensile test. The key finding in the mechanical properties of homogeneous nanocomposite in terms of reinforcement distribution, evolving due to microstructural evolution during the ARB process, is that accumulation of ratcheting strain decreases, and fatigue and post-fatigue tensile behavior significantly increases. The rupture mechanism, analyzed by scanning electron microscope, revealed that deep hemispherical-shaped dimples, a well-known feature of ductile rupture, were changed to elongated shallow shear dimples by the impact of microstructural evolution due to imposed 1000 cycles of ratcheting test.

Microstructure and mechanical properties in ultrasonic-magnetic field coaxial hybrid GTAW joints of Ti-6Al-4V

GTAW has less arc energy density and coarse joint microstructure. A novel method of Ultrasonic-Magnetic field coaxial hybrid GTAW (U-M-GTAW) was proposed, which improved upon the traditional GTAW torch. Under 140 A current and 4 mm/s speed, the results indicated that the U-M-GTAW depth-to-width ratio increased by 54.5 % compared to GTAW. Meanwhile, the surface of the joint showed a dense corrugation. The interior of the joints was all composed of martensite α', whose phase transformation obeyed the Burgers orientation relationship. The average martensite length in the U-M-GTAW weld zone was 14.8 μm, which was 33.6 % shorter than GTAW, and the length distribution was more uniform. Additionally, the U-M-GTAW joint orientation shifted from {01−10} to {−12−10}, revealing a higher texture density. The substantial precipitation of martensite in the weld zone resulted in the highest hardness, with an average microhardness of 396.8 ± 9.0 HV, marking a 12.1 % improvement over base metal. Moreover, U-M-GTAW exhibited an elongation of 9.3 %, representing a 10.7 % enhancement compared to GTAW, with deeper dimples in the fracture indicating superior plasticity. Notably, the improvements in microhardness and elongation in U-M-GTAW were primarily attributed to the reduction in martensite length and its uniform distribution under the action of ultrasonic and magnetic fields.

Dynamic tensile properties of a novel high strength and high toughness bolt steel: Constitutive models and microstructures

With the continuous increase of depth in underground engineering, rock bursts or rock explosions can cause instantaneous shock load and result in rock engineering disasters. To solve these problems, a novel high strength and high toughness (HSHT) bolt steel with constant resistance and large deformation is proposed. This study aims to investigate the dynamic constitutive models and microstructure of HSHT steel under extreme loading conditions. A series of dynamic tension tests were conducted using a Split Hopkinson Tensile Bar (SHTB) system with a high-speed camera. The results revealed that the HSHT steel exhibited a positive strain rate effect. As the strain rate increased from 1000 s−1 to 5000 s−1, the yield strength and ultimate strength of the HSHT steel increased gradually. However, no obvious changes in the uniform elongation. Specifically, the yield strength, tension strength, and uniform elongation of strain rate at 5000 s−1 were 1100 MPa, 1170 MPa, and 30%, respectively. According to the results of the SHTB tests, a modified Johnson-Cook model was proposed. Additionally, we investigated the microstructure of HSHT steel at a high strain rate through microscopic characterization techniques. A large number of fine and deep dimples were observed near the fracture of HSHT steel under dynamic loading. Moreover, the HSHT steel demonstrates a significant presence of nano-twins, which effectively impedes crack propagation both within the grain interior and along grain boundaries. The above findings reveal the relationship between mechanical behavior and microstructure in HSHT steel within dynamic loading conditions, providing valuable insights for the design of HSHT steel in underground engineering.

Exploring the influence of pin geometry on metallurgical and mechanical characteristics of dissimilar aluminum TIG welds via friction stir processing

This study explored the effect of friction stir processing (FSP) on tungsten inert gas (TIG)-welded AA6061-T6 and AA7075-T6 joints by utilizing three different tool pin geometries, namely simple cylinder (SC), threaded cylinder with triflat faces (THF), and simple square (SS). The metallurgical aspects of unprocessed and processed weld regions were analyzed and correlated with the ultimate tensile strength, impact toughness, and microhardness properties. Results revealed that the post-FSP with a THF pin transformed the coarse dendritic structures (AGS of 34.55 µm) of the TIG weld into equiaxed fine structures (AGS of 3.51 µm) and increased the UTS, impact toughness, and microhardness by 71.51%, 95.40%, and 72.46%, respectively. The joint processed with the THF pin resulted in the highest ultimate tensile strength of 279 MPa, impact toughness of 15.02 J, and microhardness of 116.13 HV in the nugget region compared to the other two pin geometries. The highest joint properties of THF pin were attributed to the formation of fine grain structures in the nugget region, high effective strain and heat generation, improved material flow, and the decimation of intermetallic precipitates with their uniform dispersion in the nugget region. The tensile fractured surface of the TIG weldment had noticeable macro voids and coarse dimples with some rough cleavage facet in the fusion region, resulting in a brittle mode of failure. However, the tensile fractured surface of TIG + FSP weldments showed ductile failure due to the presence of fine and deep dimples with tear ridges without any void.

EFFECT OF ARB PROCESS ON WEAR RESISTANCE, PLAN STRESS FRACTURE TOUGHNESS AND FORMING LIMIT DIAGRAMS OF LAMINATED Al/SiC COMPOSITES

In this study, liquid casting process is used to fabricate AA1050/SiC composites. To increase the wettability of molten Al and improve the adhesion of particles to metallic matrix, liquid casting was selected as the fabrication process. AA1050 and Nano-SiC particles were selected as metallic matrix and reinforcements, respectively. Then, wear, mechanical properties, fracture toughness and forming limit diagram of (FLD) of aluminum composite samples have been investigated experimentally. To do this, AA1050/SiC composite strips with thickness of 1 mm have been fabricated up to eight ARB passes at 300∘C. The graining was investigated via optical microscopy (OM). The ultimate tensile strength (UTS) of samples improved to 170 MPa registering 168% improvement than the initial monolithic sample. Also, the bonding quality among the layers improved by decreasing the thickness of layers at higher number of passes (increasing the plastic strain). SEM fracture surface morphology of samples after the tensile test showed that by increasing the ARB passes, shear ductile was the fracture mode. So, deep dimples are shrinking slowly relative to the annealed sample. The FLDs’ area dropped sharply for pass 1 and then improved at higher passes as the criterion of formability. Also, wear resistance of composite samples was better than monolithic sample. Moreover, at the 10th pass, the fracture toughness enhanced to the maximum value of 33.5 MPam[Formula: see text].

In situ observations of the damage behavior of the metastable β‐titanium alloy Ti5321 using synchrotron X-ray microtomography

In situ X-ray synchrotron microtomography was used to quantify the evolution of damage in the titanium alloy Ti5321 with bimodal microstructure. The results show that voids nucleate in the equiaxed primary α grains and α plates or at α/β interfaces. There exists an approximate linear relationship between volume of voids and local strain of several largest voids. The low growth rate and delay of coalescence of voids are attributed to the dispersed distribution of the α phase in the bimodal microstructure. There are no micro-cracks formed in the interior of the sample until fracture. The deep dimples in the fracture surface indicate ductile fracture. The damage mechanism of Ti5321 is discussed with the help of post-mortem SEM. To clarify the difference in damage mechanism between metastable β and α + β titanium alloys, Ti64 is also in situ tensile tested.

Experimental investigation on the heat transfer augmentation and friction factor inside tube enhanced with deep dimples

This study aims to investigate experimentally heat transfer improvement in the longitudinal and circumferential direction and pressure drop of distilled water when flowing inside deep dimpled tubes. Also, the effect of three mechanisms that cause enhancement in the thermal performance of this new tube geometry is observed. Several tests were conducted on plain and deep dimpled tubes in a laminar regime with Reynolds numbers ranging from 500 to 2250 and constant heat flux using an experimental setup. The results indicate that implementing deep dimples on the tube improves the convective heat transfer coefficient up to 3.25 times better than a smooth tube; however, the friction factor ratio increases by just 1.69 in Re = 2250. The circumferential investigation illustrated the influence of exerting dimple on the flow field and revealed how generating vortexes enhanced heat transfer. Besides, results show that modifying tube geometry causes altering the zone of different flow regimes, which can be specified by Nusselt number and friction factor figures. Since the deep dimple tube has a low improvement penalty and appropriate thermal enhancement, increased the performance evaluation criteria (PEC) in the studying region up to 2.71. Also, it has been revealed that a deep dimpled tube cannot be applicable for Reynolds numbers below 1000. However, in higher velocities, replacement of them with simple tubes in conventional heat exchangers is highly suggested.

Microstructure characterization and mechanical properties of electron beam welded joints of WRe alloy and CoCrFeNi high entropy alloys

In this study, vacuum electron beam welding was performed on WRe/CoCrFeNi alloy, resulting in joint interfaces resembling brazing. The research primarily focused on microstructure, phase composition, grain orientation and texture, interface bonding characteristics, mechanical properties, and fracture mechanisms of the welded joints. The weld zone consisted of columnar, cellular, and equiaxed regions, influenced by solidification rate. Employing the PHACOMP method, it is predicted that the introduction of W element in the weld zone tends to precipitate the FCC phase into the μ-phase. Grain competition during weld growth led to differences in grain orientation. A strong cubic texture {001} <100> was observed in the weld, enhancing its ductility. The impact of Kirkendall voids and IMCs on the bonding at the WRe/WZ interface was discussed. Microhardness of the weld increased due to grain refinement and precipitation strengthening. The joint exhibited a tensile strength of 189 MPa and an elongation of 10 %, with a fracture mechanism characterized by interface brittle fracture and fusion zone ductile fracture. The interface fracture was attributed to Kirkendall voids, IMCs, and significant residual stresses induced by material CTE mismatch. Furthermore, deep dimples and slip bands on cleavage planes at the fracture surface bottom, along with low-angle grain boundaries promoting localized slip, indicated good plasticity in the fusion zone.

Effect of strain rates on mechanical behavior, microstructure evolution and failure mechanism of extruded-annealed AZ91 magnesium alloy under room-temperature tension

Loading rate is usually considered as a significant factor affecting formability of AZ91 magnesium alloy structural components. Herein, uniaxial tensile tests are conducted on extruded-annealed AZ91 alloy under room temperature with strain rates ranging from 1 × 10−4 s−1 to 1 × 10−2 s−1. Mechanical properties, microstructure characteristics, and fracture morphologies tensioned at these different strain rates are investigated. Extruded-annealed AZ91 alloy exhibits a positive strain-rate dependence of strength and a negative strain-rate dependence of elongation. With strain rate increasing, strain rate sensitivity basically decreases while strain-hardening rate increases. At higher strain rate, the larger strength is mainly attributed to the more rapid accumulation of dislocation and the larger dislocation density, and the lower elongation is mostly owing to the more elevated level of inhomogeneous deformation related with dislocations accumulation. As strain rate increases, the area fraction of basal texture increases while that of prismatic and pyramid texture decreases in tensioned samples, which is associated with the dominant room-temperature deformation mode of basal-slip and twinning co-induced lattice rotation. With tension strain rate increasing, there are three kinds of fracture modes including ductile facture with more and deeper dimples at low strain rate, ductile-brittle facture with some dimples and cleavage planes at mediate strain rate and brittle facture with dominant cleavage planes at high strain rate.

Fabrication of Al/BN composite strips and evaluation of fracture toughness and forming limit diagram

In this study, mechanical properties, fracture toughness (FT) and forming limit diagram (FLD) of Al base composites manufactured by accumulative roll bonding (ARB) have been studies experimentally. AA1100/BN composite strips have been manufactured with thickness of 1 mm up to 10 ARB cycles at 300°C. Their strength enhanced to 168 MPa which was 248 % enhancement than the primary aluminum alloy 1100. Also, the bonding between layers enhanced by fabrication of thin layers through the thickness of composites with more plastic strains. SEM fracture morphology of composites showed that a shear ductile fracture was achieved at higher passes. So, relative to the annealed sample, deep dimples are shrinking slowly. UTS, elongation and hardness of samples improved to 169 MPa, 11.4 % and 55.6 HV after the 10 cycle, respectively. After the first pass as the criterion of formability, the area under the FLDs dropped sharply and then enhanced at higher passes. Based on the results obtained FT enhanced to 30 MPam12 at the 10th pass.

ELECTROMAGNETIC PROPERTIES, FORMING LIMIT DIAGRAMS AND FRACTURE TOUGHNESS OF LAMINATED Al/Fe2O3 COMPOSITES

In this study, electrophysical, electromagnetic and mechanical properties, fracture toughness and forming limit diagram (FLD) of Al base composite samples have been studied experimentally. All samples have been fabricated via accumulative roll bonding (ARB) process. To this purpose, AA1060/ Fe2O3 composite strips with thickness of 1 mm have been fabricated with up to eight ARB passes at 300[Formula: see text]C. In this study, magnetic Al/Fe2O3 composites reinforced with 0, 5% and 10 wt.% of Fe2O3 particles have been manufactured via ARB. The microstructure was studied by optical microscopy (OM). Also, by decreasing the thickness of layers at higher number of passes (increasing the plastic strain), the bonding quality among the layers was improved. Scanning electron microscopy (SEM) fracture surface morphology of samples after the tensile test showed that by increasing the passes, the fracture style (mode) converted to shear ductile at higher ARB passes. So, deep dimples shrink slowly and their number and depth decreased relative to the annealed sample. As the criterion of formability, the area under the FLDs dropped sharply after the first pass and then improved by increasing the passes. Results of fracture test have shown that the value of fracture toughness has been enhanced continually to the maximum value of 34.3 MPam[Formula: see text] at the 8th pass.

Evaluation of metallurgical and mechanical characteristics of the ferritic stainless steel AISI 430 produced by GTAW-based WAAM

In this work, AISI 430 ferritic stainless steel (FSS) was produced in multi-layered wall form using gas tungsten arc welding (GTAW) based wire arc additive manufacturing (WAAM), and the mechanical and metallurgical performance was evaluated. Ferrite microstructure was found on the as-printed steel with deleterious phases and needle-shaped martensite structure. The microhardness variation of the WAAM deposited steel is found to be 200–240 HV at different regions of the entire cross-sectional area. The tensile test was done on the steel to determine the ultimate tensile and yield strength, reported as 565 ± 3 and 306 ± 1 MPa. The tensile fractured surface shows the existence of more and deeper dimples which illustrates the ductile failure.

An experimental investigation of fracture toughness, mechanical properties and forming limit curves of Al composites

In the present study, accumulative roll bonding is used to fabricate Al base composites with the thickness of 1 mm. then, fracture toughness, mechanical properties and forming limit diagrams (FLD) of them have been investigated versus ARB parameters experimentally. Boron nitride (BN) particles are used as reinforcements and Al/BN composites have been manufactured up to 10 accumulative rolling passes at 300°C. after the 10th pass, the strength of composite samples reached to 168 MPa registering 248% improvement than the initial AA1100 sample. Also, the bonding quality among the composite layers improved by increasing the number of passes. A uniform scattering of Boron nitride particles and bonding strength and quality was improved at higher number of passes. Moreover, the fracture mode at higher passes was observed as shear ductile that had been changed from deep dimples (for low number of passes). The area under the FLDs, dropped sharply after the first pass and then improved at higher passes, as the criterion of formability. Finally, fracture toughness enhanced to the maximum value of 30 MPam1/2 for the composite samples fabricated with 10 passes.

Exploring the intricacies of machine learning-based optimization of electric discharge machining on squeeze cast TiB2/AA6061 composites: Insights from morphological, and microstructural aspects in the surface structure analysis of recast layer formation and worn-out analysis

Aluminium (Al) Alloy-6061/TiB2 was developed with Squeeze casting while varying composite quantities with titanium diboride (TiB2). The metallographic structure of the composite was investigated using EDS and scanning electron microscopy (SEM). The machining of developed composite is challenging with the conventional methods due to higher tool wear and surface roughness (Ra). This study analyses the output responses, and machinability of TiB2 of 15% volume reinforced AA6061 composites using Electrical Discharge Machining (EDM). The EDM operation variables such as current, pulse on time, and voltage gap were utilized to examine material removal rate (MRR), tool wear rate (TWR) and Ra employing Box–Behnken design of experiments. The MRR, TWR and Ra data acquired from various experiments were optimized considering single and multiple objectives by a hybrid approach. Machine learning (ML) was applied to predict responses using linear regression (LR), decision tree (DT) and random forest (RF). The samples' recast layer was examined using SEM, and the thickness of the recast layer was also documented. The Al6061 alloy's SEM micrographs reveal deep equiaxed dimples on its fracture surface, indicating a high level of plastic deformation before failure. TiB2 is evenly distributed as darker particles in the Al-matrix alloy with no directional-orientation. The Al6061-15 wt% TiB2 composites' fracture surfaces display deep dimples, ductile-fracture for Al6061 alloy due to higher plastic deformation, and cleavage facets in some areas. The aluminum alloy's wear pattern depicts long, extensive ploughing grooves with short cracks parallel to the sliding direction at the grooves' bottom. SEM micrographs in recast-layer formation have reported that molten metal ligaments break into droplets during flushing, exposing fresh surfaces. The aluminum alloy's groove width is larger compared to the composites. Thus, it can be observed that the wear tracks on the base Al6061 alloy are larger and deeper in comparison to the Al- 15 wt% TiB2 surface composites due to the presence of hard TiB2 particles. Also, the recast layer may be advantageous due to its wear-resistant properties. TiB2 has importance in an industry where components slide with each other it is used in disc brakes in automobiles. Compared to industry standards, single-objective optimization considerably enhanced the outcomes: MRR increased by 10.61%, TWR enriched by 25.91%, and Ra increased by 17.60%. According to an ANOVA, peak current contributed 87.88%, 98.18%, and 95.80% respectively to MRR, TWR, and Ra. It is requisite to investigate multi-objective optimization for EDM of Al6061-15 wt% TiB2 composites' owing to the diverse optimal factor combinations for responses. Ra was slightly increased by 1.14% due to simultaneous optimization utilizing hybrid techniques with Equal and Entropy weights, which diminished TWR by 11.74% and increased MRR by 11.66%. ML, particularly DT, improves machining performance by assisting productivity, durability, and cost-efficiency under changeable circumstances and raising forthcoming study possibilities.