Search Results (194)

This study presents a comprehensive bibliometric analysis of research on 2xxx series aluminum–copper (Al–Cu) alloys published between 2020 and 2025. A complete analysis of 4380 documents from 747 sources indexed in Scopus reveals sustained research growth, with publications rising from 603 in 2020 to 948 in 2025 at a compound annual growth rate of 9.5%. China dominates global output, contributing 35.7% of publications with Central South University as the leading institution (548 articles). However, China’s international collaboration rate (12.2%) remains notably lower than Western counterparts such as the United Kingdom (62.5%) and Canada (53.2%). Core journals including the Journal of Alloys and Compounds, Materials Science and Engineering: A, and Journal of Materials Research and Technology collectively account for 11.4% of total publications, conforming to Bradford’s Law concentration patterns. Keyword co-occurrence analysis revealed five distinct thematic clusters centered on microstructure–property relationships, friction stir welding and joining technologies, corrosion mechanisms, Al–Cu–Li aerospace alloys, and additive manufacturing. While life cycle modeling (K = 5993; tm = 2022.84) indicates the field is approaching maturity, by identifying emerging frontiers such as machine learning-assisted alloy design, sustainable processing routes, and multi-material joining for electric vehicles, this study offers researchers a quantitative roadmap of the Al–Cu alloy knowledge landscape and highlights strategic opportunities for future investigation. Full article

The effect of process inputs in the friction welding of Ti6Al4V alloy rods was investigated through the analysis of residual stresses, microstructure, chemical phases and hardness testing of the weld joints. The rods were welded using different combinations of process inputs. The results revealed variations in residual stresses, hardness and microstructure of the weld joints when weld inputs were varied. Peak compressive residual stresses were obtained at the centre of the weld interface, where the grains were very fine. The joints with a greater volume fraction of martensitic grains had elevated residual stress values. The maximum compressive residual stress values were obtained at the weld interface, with high hardness results. A further investigation was conducted to study the relationship between the residual stresses, microstructure and mechanical properties of the weld joint. Full article

As a solid-state joining technology, friction stir welding (FSW) exhibits significant advantages for joining aluminium alloys, including low heat input and minimal formation of intermetallic compounds, thereby enhancing joint quality and mitigating deformation. This study investigates the single-sided and double-sided FSW processes of 3 mm thick 7075-T6 aluminium alloy sheets, focusing on characterising the microstructure and mechanical properties of the joints. Experimental results show that at a rotational speed of 1500 rpm and a welding speed of 80 mm/min, the double-sided co-directional FSW joint achieves a tensile strength of 388 MPa and an elongation of 7.09%, significantly outperforming those of the other two welding paths. In the weld nugget zone (WNZ), continuous dynamic recrystallization (CDRX) occurs, generating uniformly refined equiaxed grains (average size: 1.10 μm) and facilitating the transformation of low-angle grain boundaries (LAGBs) to high-angle grain boundaries (HAGBs). Meanwhile, the strong rotated cube texture is remarkably weakened and replaced by random recrystallized brass textures with the lowest kernel average misorientation (KAM) value in the WNZ. In contrast, the thermo-mechanically affected zone (TMAZ) accumulates a high density of LAGBs due to welding-induced plastic deformation. Microhardness testing reveals a typical “W”-shaped distribution: WNZ hardness is relatively high but slightly lower than that of the base metal (BM), and the minimum hardness of the advancing side (AS) of the heat-affected zone (HAZ) is higher than that of the retreating side (RS). This study confirms that double-sided co-directional FSW crucially regulates microstructural evolution and improves the mechanical properties of 7075-T6 aluminium alloy joints, providing a viable process optimisation strategy for high-quality welding of thin-gauge sheets. Full article

Resistance spot welding (RSW) is one of the dominant joining processes in body-in-white manufacturing within the automotive industry, while the use of aluminum alloys continues to increase. This study investigates the influence of key process parameters on the spot diameter in RSW of the aluminum alloys EN AW-5182 (AL5-STD) and EN AW-6005 (AL6-HDI). Experiments were performed using industry-standard robotic welding equipment in a partially automated welding cell. Welding current, electrode force, sheet thickness (1–3 mm), and adhesive application were systematically varied. The welded joints were evaluated by destructive testing to determine spot diameter. The results show that higher welding currents increase the spot diameter for both alloys, while higher electrode forces decrease it. EN AW-5182 exhibited a high tendency toward expulsion, whereas no expulsions occurred for EN AW-6005 under identical conditions. The application of the structural adhesive BETAMATE™ 1640 consistently increased the spot diameter. Full article

Aluminum foam is attracting attention as a multifunctional, ultra-lightweight material. To apply this aluminum foam to actual industrial materials, aluminum foam plates are required. In addition, it is expected that a multi-layer aluminum foam composed of dissimilar aluminum alloy foam layers can further enhance its functionality. In this study, we attempted to fabricate a three-layer aluminum foam composed of commercially pure aluminum AA1050 and Al-Mg-Si aluminum alloy AA6061 by heating and foaming a total of three pieces of AA1050 precursor and AA6061 precursor arranged alternately, followed by immediate roller joining. It was found that, by traversing a roller immediately after foaming the AA1050 and AA6061 precursors, the aluminum foam could be joined while forming it into a flat plate. In addition, X-ray CT images of the fabricated samples revealed that material flow induced by roller traversing ruptured the surface skin layer. Numerous pores were observed within the sample, indicating pores were maintained during the roller traversing and no significant differences in porosities were identified between AA1050 aluminum foam and AA6061 aluminum foam. Furthermore, from the four-point bending test and the observation of samples after bending test, although quantitative mechanical properties were not obtained due to the as-joined samples were used for the bending test, pores were observed at the fracture surfaces, confirming that roller joining achieved seamless joining. Full article

Friction stir welding (FSW) was employed to achieve a reliable joining of 2 mm thick dissimilar metals, 6061 aluminum alloy and AZ31B magnesium alloy. This study revealed the evolution of interfacial interlocking features and their impact on the mechanical properties of the joints under different welding speeds (25–35 mm/min). The results indicate that the Al/Mg FSW joint interface exhibits a strip-like interlaced structure, the morphological characteristics of which are closely related to the welding speed. For quantitative analysis, the ratio of interlocking length to plate thickness (embedding ratio) was used as a quantitative indicator of the structural interlocking feature. As the welding speed increased from 25 mm/min to 35 mm/min, the embedding ratio decreased from 13.2 to 7.9, and the average thickness of the intermetallic compound (IMC) layer decreased from 2.71 μm to 2.19 μm. Transmission Electron Microscopy (TEM) results confirmed that the Al/Mg FSW joint interface consists of a bilayer of IMCs, specifically Al₃Mg₂ and Al₁₂Mg₁₇, with thicknesses of 220 nm and 470 nm, respectively. Tensile testing of joints with different embedding ratios demonstrated that the tensile strength of the welded joint exhibits a positive correlation with the embedding ratio, reaching a maximum of 178 MPa. Full article

Titanium alloys and copper have broad applications in aerospace, defense, and industry, but their dissimilar welding faces challenges from significant physicochemical differences and easy formation of brittle Ti-Cu intermetallic compounds, while existing methods like laser welding or friction stir welding have limitations, such as low strength or inability to weld ultra-thin plates. This study adopted cold welding to join Ti-6.5Al-1Mo-1V-2Zr alloy and 99.90% pure copper. The mechanical properties of the joint were tested, the microstructure and fracture of the weld were observed, and the phase composition of the weld was analyzed. The results show that the weld fusion zone mainly consists of Cu-based solid solution and Cu₃Ti. Low cold welding heat input reduces the Cu₃Ti content, so the joint mechanical properties do not decrease significantly. The tensile strength of the joint reaches 284 MPa, which is 83% of that of copper-based metals, and the elongation rate reaches 6.25%. Diffusion kinetics and solidification thermodynamics analyses confirm that Cu₃Ti intermetallic compounds are preferentially generated in the weld seam. Full article

Aluminum–based brazing alloys have been developed for joining 7072 high–strength aluminum alloys. However, challenges related to their high melting points and joint softening still require further exploration. This study employs a combination of first–principles calculations and experimental techniques to examine the microstructure and mechanical properties of 7072 aluminum alloy joints brazed with (Ni, Y)–modified Al–Si–Cu–Zn filler alloys. Through the virtual crystal approximation (VCA) method, it was observed that the Al–10Si–10Cu–5Zn–xNi–yY (x = 0, 1.0, 2.0, 3.0, y = 0.2, 0.4, 0.6) filler alloy exhibits excellent mechanical stability, combining both high strength and reasonable ductility. Seven brazed joint samples with varying Ni and Y contents were fabricated using melting brazing and analyzed. The findings showed that Ni reduces the liquidus temperature of the filler, narrowing the melting range. This facilitates the conversion of the brittle Al₂Cu phase into a more ductile Al₂(Cu,Ni) phase, thus enhancing joint strength. Y acts as a heterogeneous nucleation site, promoting local undercooling, increasing the nucleation rate, and refining the microstructure. When the Ni content was 2.0 wt.% and the Y content was 0.4 wt.%, the tensile strength of the brazed joint reached a peak value of 295.1 MPa. Computational predictions align with the experimental results, confirming that first–principles calculations are a reliable method for predicting the properties of aluminum alloy brazing materials. Full article

The 6xxx-series Al alloys have been used for decades because of their favorable strength-to-weight ratio, corrosion resistance, and fatigue performance. However, conventional welding techniques often induce localized weakening, as thermal effects modify the microstructure and compromise structural integrity. For nearly 70 years, AA4043 welding wire has been the primary choice for joining 6xxx-series Al alloys. Nevertheless, microstructural and mechanical property mismatches between the base metal and weld region remain key factors contributing to premature failure, while welding-induced defects further increase rupture susceptibility. Microalloying has emerged as an effective strategy for enhancing both the mechanical and thermal properties of aluminum alloys. In this study, rare-earth (RE) elements La and Ce were introduced into the AA4043 system to exploit their grain refining and mechanical strengthening capabilities. In addition, the effects of Sr modification were examined and compared with La-Ce addition. This work aims to elucidate the strengthening mechanisms associated with La-Ce-Ti microalloying in AA4043 welding wire, a topic that has rarely been systematically investigated. With 0.019Ti-0.02La-0.03Ce additions, the modified wire exhibited significant performance improvements, achieving an UTS of 204 MPa and a YS of 191 MPa—representing increases of 10.3% and 18.6%, respectively. Full article

Electromagnetic riveting (EMR) is a high-speed solid-state joining technique with growing relevance in aerospace manufacturing, particularly for titanium alloys such as Ti-6Al-4V. Although the mechanical behavior of EMR joints has been previously studied, the specific influence of die geometry on rivet deformation and joint integrity remains insufficiently understood. In this work, an explicit finite element analysis was conducted using ANSYS Explicit Dynamics to assess the effect of three die geometries (90°, 70°, and 45°) on the mechanical and thermal response of Ti-6Al-4V rivets and plates. The Johnson–Cook constitutive model was employed to capture high strain-rate deformation behavior. Key process metrics, including radial expansion, Von Mises stress, plastic work, and adiabatic temperature rise, were analyzed for each configuration. The results show that sharper die angles (90°) promote greater rivet expansion but also induce higher stress concentrations in the plates, while shallower dies (45°) produce smoother stress distributions with reduced deformation. All configurations demonstrated significant adiabatic temperature rise (approximately 250 °C) in the high-deformation zones. This indicates that thermal softening contributes to the material flow, although the process remains below the phase transformation temperature of Ti-6Al-4V. Overall, the findings highlight that die geometry critically affects stress localization and rivet interlocking, providing guidance for optimizing EMR tooling design to enhance reliability in high-performance aerospace structures. Full article

Refill friction stir spot welding (refill FSSW) is a solid-state joining technique that enables dissimilar welding between aluminum and steel alloys with minimal intermetallic compound (IMC) formation. Previous studies have focused on the interfacial mechanical performance of such joints, limited attention has been given to the localized corrosion behavior of the aluminum surface after welding, particularly in relation to microstructural evolution. This study investigates the effect of refill FSSW on the localized corrosion resistance of the aluminum surface in dissimilar joints with DP600 steel, since the Al side is typically the exposed surface in automotive service conditions. Emphasis is placed on the correlation between microstructural changes induced by the welding thermal cycle, such as grain refinement and precipitate coarsening, and localized corrosion behavior. The welded samples were characterized by optical and scanning electron microscopy, Vickers hardness measurements and potentiodynamic polarization techniques. Corrosion tests revealed a slight reduction in corrosion resistance in the stir zone compared to the base metal, mainly attributed to Mg₂Si coarsening. Pit initiation sites were associated with Al(Fe, Mn)Si and Mg₂Si precipitates. These findings offer new insights into the corrosion mechanisms acting on the aluminum surface of refill FSSW joints, supporting the development of more corrosion-resistant dissimilar structures. Full article

Additive manufacturing (AM), particularly laser-based powder bed fusion (PBF-LB), enables the production of high-strength, lightweight components made of aluminum alloys such as AlSi10Mg. However, joining these parts via welding remains a significant challenge due to weld seam porosity caused by hydrogen entrapment. This study investigated the influence of the PBF-LB process parameters, tungsten inert gas (TIG) welding settings, filler material, and post-weld T6 heat treatment on the tensile strength and porosity of welded AlSi10Mg components. Using two different layer heights (30 µm and 60 µm), plate thicknesses (3 mm and 5 mm), and varying welding conditions, a series of 10 TIG-welded sample groups were fabricated and analyzed. Microstructural, hardness, porosity, and tensile tests revealed that porosity was high across all samples (11–19%). A subsequent T6 heat treatment improved the tensile strength. Higher layer heights and thinner plates led to a higher tensile strength of the weld seam, while the addition of a filler material showed limited benefits. No other influencing factors or interactions could be found. The results emphasize the need to optimize hydrogen control in the processes, melt pool dynamics, and weld seam geometry to receive reliable joints in lightweight manufacturing of PBF-LB AlSi10Mg parts. Full article

Dissimilar material welding enables the integration of the superior properties of different materials, thereby achieving optimal structural performance and economic efficiency while meeting specific service requirements. The presence of solid-solution strengthening elements such as Ti, Co, and Al, and trace elements such as P and S, in GH3030 nickel-based superalloy leads to their segregation and the formation of intermetallic compounds in the welded joint, resulting in deterioration of joint performance. High-entropy alloys (HEAs), with their high-entropy effect and delayed diffusion effect working synergistically, can effectively suppress compositional segregation caused by uneven elemental diffusion and the formation of intermetallic compounds at interfaces, thereby improving the quality of welded joints and demonstrating great potential for dissimilar material joining. Therefore, in this study, fiber laser welding was used to effectively join AlCoCrFeNi2.1 eutectic high-entropy alloy and GH3030 nickel-based superalloy, with the expectation to improve welded joint element segregation, suppressing the formation of intermetallic compounds, and enhance the welded joint quality and its performance. The AlCoCrFeNi2.1/GH3030 joint exhibits an average yield strength of 1.31 GPa, which is significantly higher than that of the GH3030/GH3030 joint (1.07 GPa). In addition, the AlCoCrFeNi2.1/GH3030 joint shows a higher average work-hardening exponent of 0.337 compared with 0.30 for the GH3030/GH3030 joint, indicating improved plasticity. The results showed that under appropriate welding process parameters, the hardness of the weld zone, transitioning from the nickel-based superalloy to the eutectic high-entropy alloy, exhibited a stable increasing trend, and the joint exhibits good plasticity, with brittle fracture being unlikely. Full article

Titanium and its alloys are well-suited for marine engineering owing to their high specific strength and superior corrosion resistance. However, their high cost remains a key barrier to widespread marine application. Titanium/steel (Ti/Fe) dissimilar materials provide a promising solution by integrating titanium’s corrosion resistance with the high strength of steel, thereby significantly reducing costs. This review systematically assesses the potential preparation strategies for Ti/Fe dissimilar materials, such as explosive welding, rolling, high-energy beam cladding, and cold spray, to meet the large-scale application requirements in marine engineering. Advanced welding techniques for joining Ti/Fe joints are also discussed. The advantages and issues of Ni, Cu, Fe, and Al interlayers suitable for marine engineering applications in inhibiting Fe-Ti IMCs are introduced, with a focus on their potential in promoting the development of economically efficient ocean engineering. A comprehensive evaluation is conducted on the performance of Ti/Fe dissimilar materials, particularly their corrosion resistance and fatigue resistance in marine environments. This review aims to provide a reference for the theoretical research, preparation strategies, and application expansion of low-cost Ti/Fe dissimilar materials in marine engineering. Full article

Ultrasonic-assisted friction stir lap welding (FSLW) was employed to join dissimilar aluminum alloys, namely Al-7075 and Al-5052. The effect of ultrasonic power on the weld performance was systematically investigated. Increasing the ultrasonic power enhanced the material flow, resulting in a significant reduction in the cavity area in the nugget zone, from 0.37 mm² to 0.01 mm², as the ultrasonic power was increased from 0 W to 600 W. Simultaneously, increasing the ultrasonic power accelerated the dynamic recrystallization in the nugget zone, refining the grain size by 46%. This grain refinement consequently enhanced the hardness of the nugget zone, yielding an increase of approximately 10 HV. However, the excessive ultrasonic power level of 600 W also amplified the ultrasonic punch effect, inducing interfacial crack formation between Al-7075 and Al-5052 on the advancing side. These defects (cavity and interfacial crack) significantly influenced the joint failure behavior: the non-ultrasonic-assisted FSLW joints failed at the cavity, while the 600 W-ultrasonic-assisted FSLW joints failed along the interfacial crack. Comparatively, an ultrasonic power of 300 W suppressed both the cavity and interfacial crack, producing FSLW joints with the highest shear strength among all tested ultrasonic power levels (0 W, 300 W, and 600 W). Full article