Interfacial Mechanical Properties Research Articles

Microstructure Evolution and Mechanical Properties of Ta-Cladded Ni-Cr-Mo Low Alloyed Steel via Explosive Welding

The effects of welding variables (stand-off distance and explosive thickness) on the interfacial microstructure evolution and mechanical properties of explosively welded Ta alloy to Ni-Cr-Mo low alloyed steel have been investigated. Regardless of welding conditions (a stand-off distance of 3-5 mm and explosive thickness of 40-80 mm), the Ta/steel interface consistently exhibited a wavy configuration. This wavy interface facilitated the formation of vortex, resulting in strong interlocking. The height of the vortex increased with a larger stand-off distance at a fixed explosive thickness of 60 mm. Similarly, increasing the explosive thickness at a stand-off distance of 3 mm also resulted in a greater vortex height. The explosive weldability window, plotting the collision angle (<i>β</i>) against the collision point velocity (<i>v<sub>c</sub></i>), was successfully established for the dissimilar Ta and steel plates. The upper limit prediction with <i>N</i>=0.11, as proposed by Wittman, best matched the experimental results. This guided the determination of the optimal condition, which was a standoff distance of 3 mm and an explosive thickness of 40 mm. A vortex melted zone (VMZ) was identified, which resulted from the dynamic intermixing of Ta and steel, combined with localized melting caused by high-energy collisions and heat accumulation. The VMZ surrounded by a highly deformed Ta alloy, showed the highest hardness. Near the interface on the steel side, a fine recrystallized grain structure was observed. No significant inter-diffusion was detected at the wavy Ta/steel interface. The tension-shear properties of the wavy interface, which was subjected to loading parallel to interface, showed a good balance of strength and ductility, confirming the soundness of Ta/steel interface.

Interface Microstructure and Mechanical Properties of Nickel/Steel Bimetal Composite Pipe Fabricated by Explosive Welding

In this paper, the microstructure and mechanical properties at the interface of Incoloy825/X65 bimetallic composite pipe achieved by explosive welding were systematically studied. Results show that a periodic wavy bonding interface was formed between the Incoloy825 and X65 due to the jets caused by the high-impact stresses during explosive welding, which was beneficial for improving the bonding strength of the Incoloy825 and X65. Atomic diffusion and localized melting occurred near the interface during explosive welding. Some fine crystal grains were generated in the vicinity of the interface due to the strong plastic deformation and dynamic recrystallization, whereas some elongated grains growing in the perpendicular direction to the interface were found in the wider localized melted zone. Room temperature nanoindentation test showed that due to the existence of fine grains resulting from the recrystallization at the interface, the hardness of the interface was higher than that of the base metals. Voids and defects were prone to appearing in the vortex regions near the interface, where the weak point in the interface was located.

Molecular dynamics investigation of epoxy resin adsorption mechanisms on clay surfaces and the mechanical properties of epoxy resin-clay

The strength of natural clay can be improved with epoxy resins. However, nanoscale curing mechanisms remain poorly understood, which is essential for enhancing stability. In this study, molecular dynamics simulation was employed to calculate the quantity of interface hydrogen bonds, adsorption energy, radius of gyration, and mechanical properties of clay cured by diglycidyl ether of bisphenol-A epoxy resin (DGEBA), diglycidyl ether 4,4’-dihydroxy diphenyl sulfone (DGEDDS), and Aliphatic epoxidation of olefin resin (AEOR). Adsorption behavior and mechanical properties of the clay cured by three epoxy resins were investigated: (1) The chain structure of AEOR led to 18.2% more hydrogen bonds than DGEBA and 59.1% more than DGEDDS. (2) The simulated adsorption energies for DGEBA, DGEDDS, and AEOR with kaolinite were 92.59, 98.25, and 116.87 kcal·mol−1, respectively. (3) The bulk and shear modulus of kaolinite increased by 4.93% and 4.80% when using AEOR. The interface stability and mechanical properties of kaolinite were also improved through strong hydrogen bonds and high adsorption energy. (4) The improvement in Young’s modulus of kaolinite was most significant with AEOR, followed by DGEDDS. AEOR excelled in the Z direction, while DGEDDS excelled in the X and Y directions. This research provided a theoretical foundation to effectively improve the properties of clay using epoxy resins.

Effects of Surface Roughness Obtained by Milling on Interface Bonding Quality for 316H during Metal Additive Forging

The metallurgical bonding quality of bonded joints is affected by the substrate surface condition in metal additive forging process, and the surface roughness serves as a critical indicator for the surface condition. Nevertheless, the effect of surface roughness obtained by milling on interface bonding quality(IBQ) remains unclear, resulting in the lack of effective evaluation criteria for surface roughness in the milling process. This study prepared samples with various surface roughness through milling, and introduced three parameters, Ra, Rc, and Rsm, to quantify surface roughness. The interfacial morphology, elemental distribution, and mechanical properties were used to characterize the IBQ, and the influence of surface roughness on the IBQ was finally revealed. The results show that a reduction in surface roughness obtained by milling leads to an improvement in interfacial bonding, more uniform elemental distribution, and enhanced mechanical properties, all of which were related to the size of the initial voids and the dynamic recrystallization mechanism of the bonding interface. And the interface bonding process with various surface roughness involves grain boundary bulging and continuous dynamic recrystallization mechanisms. Finally, the Ra 1.2 μm was recommended as the evaluation criteria in milling process, and a high-feed face milling cutter equipped with wiper edge was suggested for machining to achieve high-quality and high-efficiency cutting of the substrate. This study provide a theoretical basis and practical guidance for the efficient acquisition of substrate surfaces suitable for interface bonding in metal additive forging process.

Interfacial reaction and mechanical properties of Sn-Bi Cu core solder joints

Interfacial reaction and mechanical properties of Sn-Bi Cu core solder joints

Pressure-less joining SiCf/SiC tube and Kovar alloy with AgCuInTi filler: interfacial reactions and mechanical properties

Pressure-less joining SiCf/SiC tube and Kovar alloy with AgCuInTi filler: interfacial reactions and mechanical properties

Interfacial microstructure evolution and mechanical characterization of brazed Al2O3 joints with Ni‒Ti interlayer: An experimental and theoretical approach

Reliable brazing joints of Al2O3 ceramics were obtained using an active Ni‒Ti interlayer under vacuum conditions. The interfacial microstructure and mechanical properties of the joints were studied. The structural, electronic, and elastic properties of the primary interfacial reaction phases were determined using first–principles calculations. After brazing at 1320 °C for 30 min, Ni2Ti4O layer and columnar AlNi2Ti formed at the interface adjacent to the Al2O3 substrate. With increasing brazing temperature between 1300 °C and 1380 °C, Ni2Ti4O layer thickened gradually, and the AlNi2Ti became increasingly longer. As brazing temperature reached 1400 °C, TiO was formed at the interface, and the Ni2Ti4O content decreased significantly; moreover, bulk AlNi2Ti and TiNi3 were distributed in the brazing seam. The highest shear strength of 129 MPa was achieved when brazed at 1350 °C for 30 min. According to the first–principles calculations, Ni2Ti4O is more readily formed than AlNi2Ti, whereas AlNi2Ti exhibits greater stability than Ni2Ti4O. Both AlNi2Ti and Ni2Ti4O possess metallic bonds, contributing to the adhesion of the filler metal to the Al2O3 substrates. The calculated modulus and Poisson’s ratio indicate that both AlNi2Ti and Ni2Ti4O exhibit ductile characteristics, which assist in relieving residual stress within the joint.

Improved Synchronous Characterization Theory for Surface and Interface Mechanical Properties of Thin-Film/Substrate Systems: A Theoretical Study on Shaft-Loaded Blister Test Technique

In this paper, the previously proposed shaft-loaded blister test technique for the synchronous characterization of the surface and interface mechanical properties of a thin-film/substrate system is further studied theoretically. The large deflection problem of the steady shaft-loaded blistering thin film is reformulated by surrendering the small-rotation-angle assumption of the membrane, which was previously adopted in the out-of-plane and in-plane equilibrium and radial geometric equations. A new and more accurate analytical solution to this large deflection problem is presented and is used to improve the previously presented synchronous characterization theory. The new analytical solution is numerically compared with the previous analytical solution to confirm the superiority of the new analytical solution over the previous analytical solution. An experiment is conducted to verify the beneficial effect of the improved synchronous characterization theory on improving the characterization accuracy.

Effects of oil-water interfacial properties on protein structuring and droplet deformation in high moisture meat analogues containing oil

Adding oil to high moisture meat analogues (HMMA) can increase juiciness, and can be achieved by incorporating emulsion droplets during extrusion. Since these droplets can coalesce when subjected to high shear, selecting appropriate emulsion stabilisers is important. For several commercial plant-protein emulsion stabilisers, it was investigated how oil-water interfacial mechanical properties affect droplet deformation and protein structuring in extrusion of HMMAs. Emulsions with 10 wt% or 15 wt% oil, stabilised by potato protein isolates (POPI-1 (Rich in patatin) and POPI-2 (rich in protease inhibitor)) and pea protein isolate PPI, were used to make extrudates with 5.7 wt% and 8.5 wt% oil, respectively. In 8.5 wt%-extrudates, POPI-2 had the most oil leakage from the cooling die, while PPI had the smallest amount despite having softer and more stretchable interfaces. Blade-cutting tests showed the highest maximum force for 8.5 wt%-extrudates with POPI-1, likely because POPI-1 formed the stiffest interfaces. Tensile stress testing showed the largest fracture strain in 8.5% wt%-extrudates with PPI, corresponding to its longer wedge length. Multiphoton excitation microscopy was used to visualise the extrudates protein structure and oil droplets. This showed that droplets near the surface of the extrudate were less deformed than droplets in the centre. There were only small differences between protein stabilisers regarding oil droplet deformation, indicating droplet deformation was dominated by deformation of the protein matrix. The O/W interfacial properties significantly affected oil leakage, cutting force, and tensile strength of extrudates. These results are important to consider when designing emulsions for HMMAs processed by extruders.

ZnO modified carbon fiber-matrix interfacial evaluation via nanoscale digital image correlation and nanoindentation

Improving the adherence of the fiber-matrix interface is an important step for enhancing the capabilities of polymer composites. In this study, carbon fibers were modified by growing zinc oxide (ZnO) nanorods on the fiber surface using a hydrothermal approach, with the aim of increasing the interfacial area and enhancing the friction between the fiber and the matrix. To fully understand the deformation mechanisms at the interface, a microscale evaluation combining nanoindentation with digital image correlation (DIC) for mapping the deformations by using nanoscale speckles is developed in this work. The main objective of this research was to develop a protocol for speckling the modified single fiber composite and show that DIC can be used in microscopic level and to evaluate the fiber-matrix interface by means of nano indentation. The speckle pattern was created using Ti nano powder and used to generate the strain maps in the fiber-matrix interface region. A comparative analysis of DIC results from ZnO modified carbon fibers has shown that shear strains around the interfacial boundary are 60 % reduced on average, as compared to neat carbon fibers, across all nano indentations from 8mN to 65mN of peak load. Results used direct strain measurements to confirm that modification by ZnO growth on the surface of individual fibers has a significant benefit to the interfacial mechanical properties of fiber-matrix composites.

Electrochemical behavior and microstructure of diffusion welding of zirconium alloy and super duplex stainless steel

In this study, the effect of welding temperature on interface microstructure, mechanical properties, and electrochemical behavior of diffusion welded joints (DWJs) of zirconium alloy (ZrA, Zr702 grade) and super duplex stainless steel (2205 duplex stainless steel grade) were investigated. Alloys were welded in a vacuum atmosphere at four different temperatures (800, 850, 900, and 925 °C) for 75min under 4MPa compressive pressure. The optical, scanning electron microscopy, electron probe micro-analyzer, and X-ray diffraction techniques were used to characterize the interfacial microstructure of the DWJs. Layers of intermetallics were formed along the welded interface at 850 °C and above welding temperatures. At 850 °C, a single reaction layer (phase mixture of ZrFe2+ZrCr2) was observed; however, bilayers (ZrFe2+ZrCr2 and Fe2Zr+FeZr3 phase mixtures), and triple layers (ZrFe2+ZrCr2, Fe2Zr+FeZr3, and β-Zr+FeZr3 phase mixtures) were observed at the welded interface of the joints processed at 900 and 925 °C, respectively. Width of the reaction layer (phase mixtures) increases with an increase in the welding temperature. The DWJs processed at 900 °C reach the maximum joint strength of ~312MPa along with ~6.4% ductility. For corrosion analysis, studies of the base alloys and DWJs in 0.1mol/L HCl and 0.1mol/L NaOH solutions separately using electrochemical techniques, such as open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization were undertaken.

Insights into Structural Changes During Scratch Deformation of Ductile Coating Systems: Plastic Flow, Microstructural Transformations, and Crack Development

This study investigates the structural changes occurring during the scratch deformation of ductile materials, focusing on a composite aluminum (Al) coating on a steel substrate fabricated using a solid-state aluminizing technique. By analyzing the results of the scratch test with transmission electron microscopy (TEM) and focused ion beam (FIB) techniques, the research provides a detailed examination of plastic flow, microstructural transformations, and crack development. Results demonstrate that strong adhesion at the interface and similar mechanical properties between steel and Al layers facilitate co-deformation, crucial for maintaining the integrity of the composite structure. The study features the formation of a rolling-like laminated structure and significant grain refinement in both the steel and Al components, driven by plastic deformation. Observed atomic-scale intermixing and the formation of an amorphous interlayer highlight extensive material interactions during deformation. The visualization of crack progression using FIB allows for an in-depth understanding of the fracture process. Subsurface cracks initiate within the thin Al interlayer and propagate toward the surface, evolving through the coalescence of nanopores into microvoids and larger cavities, ultimately leading to crack propagation. Secondary internal cracks may arise due to stress fields generated by the primary crack, contributing to a complex network of internal cracks.

Effect of bell annealing on the interface microstructure and mechanical properties of titanium/steel composite plates prepared by hot rolling

This study investigates the effect of bell annealing (600°C-750°C/3 h-15 h) on the interfacial microstructure and mechanical characteristics of hot-rolled titanium/steel (Ti/steel) bi-metallic plates, aiming to improve their mechanical performance and deformation compatibility. The interfacial bonding mechanism and growth process of the interfacial TiC layer were studied using multi-scale characterization. The microstructural evolution during annealing and the effect of the TiC layer on element interdiffusion were considered. Results show that the TiC interlayer inhibits Ti and Fe diffusion, preventing undesirable Ti-Fe phases, and the TiC layer thickens towards the Ti side. Higher annealing temperatures and longer times worsened the grain size difference between the Ti and steel layers and produced a thick TiC layer, severely degrading deformation compatibility. Microcracks, caused by severe lattice mismatch, are mostly initial at the α-Fe/TiC interface during plastic deformation. Thin to moderate TiC layers resulted in a combination of ductile and brittle fractures, while thick layers led to brittle fractures. In terms of mechanical properties, the ultimate tensile strength (UTS), yield strength (YS), shear strength, and elongation (EL) of the hot-rolled composite plate were measured at 337 MPa, 232 MPa, 238 MPa, and 29%, respectively. All annealed samples exhibited a reduction in UTS, YS, and shear strength compared to the hot-rolled state; however, they demonstrated improved elongation and deformation compatibility, with the elongation achieving its optimal value at 650°C-3 h. The annealing, at 650°C for 3 h, was identified as the optimal condition for post-rolling heat treatment, resulting in a composite plate with a comprehensive mechanical performance characterized by UTS, YS, shear strength, and EL values of 267 MPa, 127 MPa, 171 MPa, and 46%, respectively.

Effect of electromagnetic stirring on interfacial microstructure and mechanical properties of Al/Mg bimetal produced by lost foam compound casting

The Al/Mg bimetal was fabricated using a novel spiral magnetic field-assisted lost foam compound casting (LFCC) process, and the effects of electromagnetic stirring (EMS) on the interfacial microstructure and mechanical properties of the Al/Mg bimetal were investigated. The results indicated that the interface of the Al/Mg bimetal without EMS consisted of Al–Mg intermetallic compounds area (IMCs area) and Al–Mg eutectic area (E area). The Mg2Si particles exhibited a reticulated agglomeration in the IMCs area, and a continuous oxide film was present at the junction of the IMCs area and E area. During shear strength measurement, interface cracks propagated along the oxide film until interface fracture occurred, leading to lower bonding strength at the interface. With EMS applied, there was no change in the phase composition of the Al/Mg interface. The EMS facilitated the diffusion of Si elements in the interface, resulting in the refinement and dispersion of the Mg2Si particles within the IMCs area. Moreover, the Mg2Si content around the oxide film significantly increased, the oxide film remained but became discontinuous. During shear strength measurement, the interface cracks didn’t propagate along the oxide film but extended from the IMCs area to the E area, as a result, the shear strength increased by 29.1% compared to the samples without EMS. The study results demonstrated that applying EMS during the lost foam casting process is a feasible method for improving the microstructure and properties of the Al/Mg bimetals.

Optimizing Surface Characteristics of Stainless Steel (SUS) for Enhanced Adhesion in Heterojunction Bilayer SUS/Polyamide 66 Composites.

The increasing environmental concerns and stringent regulations targeting emissions and energy efficiency necessitate innovative material solutions that not only comply with these standards but also enhance performance and sustainability. This study investigates the potential of heterojunction bilayer composites comprising stainless steel (SUS) and polyamide 66 (PA66), aiming to improve fuel efficiency and reduce harmful emissions by achieving lightweight materials. Joining a polymer to SUS is challenging due to the differing physical and chemical properties of each material. To address this, various surface treatment techniques such as blasting, plasma, annealing, and etching were systematically studied to determine their effects on the microstructural, chemical, and mechanical properties of the SUS surface, thereby identifying mechanisms that improve adhesion. Chemical etching using HNO3/HCl and CuSO4/HCl increased surface roughness and mechanical properties, but these properties decreased after annealing. In contrast, K3Fe(CN)6/NaOH treatment increased the lap shear strength after annealing. Blasting increased surface roughness and toughness with increasing spray pressure and further enhanced these properties after annealing. Contact angle measurements indicated that the hydrophilicity of the SUS surface improved with surface treatment and further improved due to microstructure formation after annealing. This study demonstrates that customized surface treatments can significantly enhance the interfacial adhesion and mechanical properties of SUS/polymer heterojunction bilayer composites, and further research is recommended to explore the long-term stability and durability of these treatments under various environmental conditions.

Evaluation on the diffusion-fusion properties and interfacial mechanical behavior of virgin and aged asphalt

To investigate the regeneration mechanisms of rejuvenated asphalt mixtures, molecular simulation techniques were employed to research virgin and aged asphalt's fusion characteristics and interface mechanical properties. The blended zone was identified based on relative density distribution, and a molecular-scale calculation method for the Degree of binder Blended (DOB) between virgin and aged asphalt was proposed. Finally, the influence of DOB on the mechanical properties of the asphalt-aggregate interface was evaluated through interface pull-out tests. The results revealed that the proposed molecular-scale DOB calculation method effectively assessed the blending effectiveness between virgin and aged asphalt. Higher degrees of asphalt aging made it more challenging for aged asphalt to fuse with virgin asphalt, while elevated temperatures facilitated diffusion fusion between them. Under tensile loading, initial cracks were primarily initiated from the rejuvenated asphalt's blended zone. This region represented the weakest area within the interface system and was prone to fracture under load. The increase in DOB significantly improved the interfacial properties of recycled asphalt, with the increase in DOB the interfacial tensile strength increased by 4%–14% and the fracture energy increased by 10%–19%. However, this enhancement effect diminished with an increased degree of asphalt aging. At the molecular scale, increasing DOB improved the interface strength and deformation resistance of rejuvenated asphalt. The molecular simulation results provide theoretical guidance for evaluating the fusion degree of aged asphalt in RAP materials and determining the utilization efficiency of aged asphalt.

Study on microstructure and mechanical properties of vacuum brazing TC4 titanium alloy with Ti-37.5Zr-15Cu-10Ni amorphous filler metal

Ti-37.5Zr-15Cu-10Ni amorphous brazing filler metal was employed to join TC4 titanium alloy by vacuum brazing. This work investigated the effect of brazing temperature and holding time on the interfacial microstructure and mechanical properties of TC4/Ti-Zr-Cu-Ni/TC4 joints. Results indicate that the increasing brazing temperature above 900 ℃ and prolonging the holding time both promoted the formation of α-Ti + (Ti, Zr)2(Cu, Ni) eutectoid phases and acicular Widmanstätten. The shear strength of joints increased with elevating brazing temperature and the maximum value was 223.9 MPa obtained at 940 °C. When prolonging the holding time at the brazing temperature of 900 ℃, the shear strength increased firstly and then dropped. When the brazing temperature was 900 °C, the microhardness in the reaction layer was highest, reaching 572 HV0.1, which was caused by the formation of (Ti, Zr)2(Cu, Ni) intermetallic compounds. As the brazing temperature rose to 940 °C, the microhardness in the reaction layer decreased to 427.5 HV0.1.

Influence of Ni‐Coating Thickness on Interface Microstructure and Mechanical Properties of Mg/Ti Bimetal via Compound Casting

In this article, the influence of Nickel (Ni)coating thickness on the interfacial microstructure and mechanical properties of AZ91D/Ti–6Al–4 V bimetal fabricated by compound casting is investigated. In the results, it is shown that the Ni coating and its thickness have a significant effect on the interfacial phase compositions and mechanical properties of AZ91D/Ti–6Al–4 V bimetal. At a Ni‐coating thickness of 6.5–27.3 μm, it transforms into α‐Mg + Mg2Ni eutectic structures + blocky τ‐Ni2Mg3Al ternary compounds at the interface zone. When the Ni‐coating thickness increases to 36.1 μm, part of the Ni coating remains, and the interface layer forms, comprising the Ni solid solution layer, Mg2Ni layer, τ‐Ni2Mg3Al ternary compounds, and α‐Mg + τ‐Ni2Mg3Al particles from Ti–6Al–4 V to AZ91D side in sequence. The microhardness of the interface zone is lower than that of the Ti–6Al–4 V but higher than AZ91D. The bimetal shear strength reaches a maximum value of 87.6 MPa at a Ni‐coating thickness of 19.7 μm enhanced by 78.5% in comparison with that of the bimetal without Ni coating. The results are helpful to further enrich the interface control method of compound casting of Ti/Mg bimetal and determine the ideal interlayer thickness for maximizing interface strength.

Understanding the effect of holding time on interfacial microstructure evolution and mechanical properties of Ti3AlC2/Zr-4 brazed joints

In this work, the brazing of Zircaloy-4 (Zr-4) to Ti3AlC2 ceramic was investigated using a Ti–13Zr–21Cu–9Ni (wt.%) amorphous alloy at 930 °C with a holding time of 5–60 min. The typical multilayer structure of the joint was carefully characterized as Ti3AlC2/ZrC/Zr [Ti]ss + [Zr(Ti)]2 [Cu(Ni)]/Zr [Ti]ss/Zr-4. Ti3AlC2 was decomposed into TiCx due to the de-intercalation of Al, and Zr-4 dissolved into the molten amorphous TiZrCuNi fillers to form a Zr-based alloy which reacted with TiCx to form a ZrC particle layer on the Ti3AlC2 side. The microstructures and mechanical properties of the brazed joint were significantly influenced by dwell time, and the underlying evolution mechanisms were addressed based on the considerations of mutual dissolution, diffusion, and reaction among Ti3AlC2, Zr-4, and molten amorphous alloys. With the extension of holding time, the amount of [Zr(Ti)]2 [Cu(Ni)] in the brazed joints decreased gradually, while the ZrC layer thickened with (Ti, Zr)ss formed around the ZrC particles. The maximum shear strength of the joint, with an average strength of 187 ± 34 MPa, was achieved by brazing at 930 °C for 5 min. A detailed fracture analysis was conducted to determine the failure mechanism. This work provides a reference for brazing other MAX phase materials and alloys.

Effects of graphene nano particles on interfacial microstructure and mechanical properties of Al7150/B4C hybrid nanocomposite fabricated by novel double ultrasonic two stage stir casting technique

In the present research, an Al7150 alloys-based hybrid nanocomposite was fabricated by incorporating boron carbide and graphene nanoparticles through a novel fabrication method of double ultrasonic two-stage stir casting. Initially, the Al-B4C nanocomposite was optimized based on better microstructural and mechanical properties, and then a hybrid nanocomposite was prepared by incorporating graphene nanoparticles into the optimized Al-B4C nanocomposite. Homogeneous dispersion of graphene and boron carbide nanoparticles in Al7150 matrix was successfully achieved due to the double ultrasonic effect analyzed by Field Emission Scanning Electron Microscopy (FESEM) and High Resolution Transmission Electron Microscopy (HRTEM) analysis. Significant dispersion of nanoreinforcements with enhanced interfacial bonding and dislocation strengthening improved the microstructural and mechanical properties of the Orovan reinforced hybrid nanocomposite. The Vickers microhardness and ultimate tensile strength were improved by 19 % and 47 %, respectively, for the optimized Al-B4C nanocomposite compared to base metal. However, the Vickers microhardness and ultimate tensile strength were significantly improved by 36 % and 57 %, respectively, for the optimized hybrid nanocomposite compared to the base material (BM). The hard AlB2, Al3BC and Al4C3 phases are formed due to the reaction between the matrix and reinforcement during solidification and act as reinforcement within the matrix and resist dislocation movements, resulting in a significant improvement in the mechanical properties of the nanocomposite. Fractography analysis by SEM also confirms the enhanced bonding of graphene nanoparticles as it deforms/slips during fracture and supports the effect of double ultrasonication on the tearing of boron carbide nanoparticles.