Precipitation-hardened Aluminum Alloys Research Articles

Laser powder bed fusion of high-strength crack-free Al7075 alloy with the in-situ formation of TiB2/Al3Ti-reinforced phases and nucleation agents

The existence of solidification cracks caused by columnar grains in precipitation-hardened aluminium alloys limit the applicability of Al7075 components manufactured via laser powder bed fusion (LPBF) additive manufacturing. A novel approach was developed to co-incorporate submicron-sized B and micron-grade Ti6Al4V to eliminate hot cracks and to effectively transform coarse columnar grains into fine equiaxed grains, thus improving the mechanical performance of LPBF-fabricated modified Al7075 material. The grain refinement was mainly attributable to the heterogeneous nucleation promoted by the combination of in-situ-formed L12-Al3Ti and TiB2 nano-sized phases. After an optimised T6 heat treatment, excellent comprehensive mechanical properties were achieved, with a tensile strength of 460 MPa and an elongation of 13 %. This research provides an efficient and cost-effective path for addressing crack-sensitive metallic materials used for LPBF additive manufacturing processes.

High strain rate tensile deformation of similar and dissimilar AA6082 and AA7075 friction-stir-welded blanks

Friction-stir-welding process has become an established solid-state technique for joining of dissimilar lightweight materials over the past decade by overcoming fundamental welding challenges such as solidification cracking, phase segregation and surface oxidation. Despite these unique capabilities, the resulting microstructure feature in the weld zone consisting of fine grains with a high dislocation density, challenges further heat treatment and forming processes. Hence, a high solution annealing temperature results in degradation of the adjusted microstructure and in a lower to reduced mechanical properties in case of dissimilar joints of precipitation-hardenable aluminum alloys. Subsequent hot forming therefore involves a great effort and requires further heat treatment steps. Thus, the present study investigates the effect of a recently introduced novel thermo-mechanical forming process on local deformation behavior of similar as well as dissimilar joints processed by friction-stir-welding technique of thin-walled AA6082 and AA7075 blanks. To avoid the complete elimination of the adjusted microstructure, the welding process is performed after a thermo-mechanical process consisting of solution annealing, die cooling and peak aging. Uniaxial tensile tests are then carried out at high strain rates ranging from ε˙ = 40 s-1 to ε˙ = 400 s-1. The results show an increase in yield and ultimate tensile strength as well as in total elongation after failure with increasing strain rates. As the strain rate increases, the flow stress of similar weld of AA7075 is higher than those of AA6082 and the dissimilar weld of AA6082 and AA7075. Local deformation measurements reveal higher strain localization in the welded zone for similar welds, which leads to micro-crack initiation and failure due to strain accumulation. Microstructure analysis shows very fine equiaxed grain structure in the nugget zone and homogenous distribution of precipitates after friction stir welding process, which explain the plastic deformation behavior.

Influence of the process time on a self-piercing riveting process with tumbling kinematic

The increasing significance of ecological responsibility, stricter political regulations and economic objectives are driving innovation in research fields such as lightweight construction. One of the most important popular methods is the use of multi-material systems. Due to the different geometric and mechanical properties of the various materials used, resource efficient applications and utilizations are possible. Great challenges arise for the joining processes to realize these multi-material systems, since conventional joining processes reach their limits. In the field of mechanical joining processes, there are continuously new approaches, such as superimposing the punch in a self-piercing riveting process with a tumbling kinematic, to increase the number of adaptable process parameters and enhance the process control. Through various preliminary tests, a good understanding of the process has been developed, which allows to directly control the geometric joint parameters by configuring the tumbling strategy. A major challenge, particularly with regard to future industrial applications, is the process time, which is comparatively high due to the tumbling kinematics. In the investigations, a reduction of approximately 90% of the process time is targeted by adapting the joining and tumbling strategy. Therefore, the correlation of the traverse velocity and the tumbling velocity are examined in a gradual series of experiments. To represent realistic applications, the experiments are carried out with a dual-phase steel and a precipitation-hardening aluminum alloy. For identifying the influence of the process parameters on the joining process, a constant rivet–die combination is applied. Further, the examination of force–displacement curves is conducted. Moreover, the determination of geometric joint parameters is reliant upon macrographs to assess the influence of the joining time on the geometric joint formation. The test results show that a significant increase in joining speed with a resulting reduction in process time is feasible. Although the joining properties are affected, reliable joining is possible. In particular, the shaft thickness of the rivet is influenced by the varying proportion of the tumbling process in the joining operation and increases with higher joining speeds.

Effect of equal-channel angular pressing on microstructure, aging kinetics and impact behavior in a 7075 aluminum alloy

Among the precipitation hardenable 7xxx series aluminum alloys, AA7075 alloys (one of the most important engineering alloys) due to their low density (lightweight), high toughness and strength, and enhanced fatigue behavior have been used over the years in aerospace, aircraft, automotive, construction and marine applications. In the present study, the influence of the artificial aging through conventional heat treatment (i.e., precipitation hardening) and the thermomechanical treatment (equal-channel angular pressing (ECAP) + post-ECAP aging) on the quasi-static tensile, impact toughness and precipitation behavior as well as on the microstructure of an AA7075 alloy is investigated systematically. The results indicate that the ECAP process as well as post-ECAP aging result in considerably increased strength and hardness of the AA7075 alloys because of the superimposed effects of grain boundary strengthening (Hall-Petch relation), strain hardening (by means of the increased dislocation density) and precipitation hardening (due to the fine precipitates formed in Al matrix). Multi-pass ECAP processing has been found to result in a considerable decrease of the impact toughness (from 15.3 J·cm−2 to 7.6 J·cm−2) associated with the failure mode (i.e., ductile-to-brittle transition) of the AA7075 alloys, whereas the artificial peak aging leads to a marked improvement (∼67 %) in the impact toughness in ECAPed conditions. Moreover, the ECAP process noticeably accelerates the precipitation kinetics of AA7075 alloys: The peak aging time in the ECAPed alloy is reduced significantly – from 30 h to 4 h. The results of the present study provide a deeper understanding of the combination of ECAP and heat treatment, and their effect on the fracture mode and toughness under impact loading, the aging kinetics and the microstructural evolution of an AA7075 alloy.

Impact Toughness of Selected Precipitation Hardening Aluminium Alloys

Impact Toughness of Selected Precipitation Hardening Aluminium Alloys

Ultrasound-assisted material characterization: An innovative method for the non-destructive in-situ detection of microstructural changes of high-strength aluminum alloys

The use of aluminum alloys in conjunction with thermal-assisted forming techniques permits the production of high-strength and geometrically complicated components without failure. By using innovative, temperature-dependent production techniques, it is possible to manufacture components with tailored properties. So far, however, it is not possible to characterize the microstructural behavior under thermal and mechanical load in real-time. Using a novel characterization method, which is based on the principle of laser ultrasonic testing, it has become possible to record contact-free and non-destructive microstructural changes in-situ during thermo-mechanical treatment. This allows the interaction-free detection of thermal as well as mechanical effects during thermal-supported forming operations. In this research work, the temperature-dependent behavior during the quenching and aging process of the precipitation-hardenable aluminum alloy AA6082 for a tailor-quenched forming process is recorded in real-time using laser ultrasonic techniques. First, the effects of different tool temperatures on quenching rates and material properties were investigated using conventional characterization methods, including temperature measurement, hardness and tensile tests. It was shown that a die temperature of 325 °C leads to the lowest material hardness and strength. Subsequently, the results were compared with the novel, non-destructive in-situ testing method and validated using microstructural analysis. It was proven, that microstructural changes can be identified during varying quench and aging operations. Thus, the influence of different process parameters on the microstructural and mechanical development of aluminum components can be detected in-situ for the first time.

High-Throughput Simulations of Phase Precipitation in Additively Manufactured Al Alloy

Additive manufacturing (AM) provides numerous advantages compared to conventional manufacturing methods, such as high design freedom and low material waste. Among the available materials, precipitation-hardenable aluminum alloys are highly attractive for AM due to their high specific strength and low density. Precise control of the processing conditions during AM and post heat treatment (HT) is required to tailor the final mechanical properties. Consequently, many variables, such as the chemical composition and process and HT parameters, must be considered to design suitable alloys for AM. Experimental investigations are, however, limited in variation of these variables. Therefore, computational alloy design approaches allowing for a faster evaluation of many possible variations must be developed. This work presents a high-throughput approach to determine the precipitation kinetics and thermodynamic properties based on the CALculation of PHAse Diagrams (CALPHAD) method. The developed approach is successfully validated for an Al-Mg-Si-Ti-Fe alloy and is applied to screen 243 combinations of chemical compositions and HT parameters. The results confirm the microstructural stability of the Al-Mg-Si-Ti-Fe system to small composition variations.

Multiscale modeling of particle-induced damage in AA7075 aluminum sheet at large plastic strains

Large plastic deformation and ductile damage in precipitation hardening aluminum alloy AA7075 is driven by plastic flow in the vicinity of particles as well as fracture and decohesion of second phase particles embedded in the matrix. The current work investigates the deformation and damage characteristics of Fe-rich intermetallic particles, and η and θ precipitates in AA7075-O sheet. A multiscale model simulation methodology is presented and applied to analyze large-scale plastic deformation and damage characteristics. The methodology utilizes nanoscale molecular dynamics simulation to obtain matrix-particle interface strength properties and Weibull statistics to capture experimental fracture characteristics of particles. The above sub-models are incorporated within a 2-D real particle microstructure-based finite element model to conduct a comparative study of the roles of decohesion and fracture in the development of plasticity and void damage in AA7075-O sheet. In addition, in-situ SEM uniaxial tensile tests are carried out to assess the effectiveness of the simulation methodology and to compare the experimental and numerical results. Post-test high resolution X-ray computed tomography (HR-XCT) was also carried out to qualitatively observe particle-induced voiding in the material. The numerical methodology is shown to capture well the experimental trends in damage evolution of the individual particles. It is observed that particle damage is a function of inherent particle properties, their morphological features, and matrix strain localization characteristics. Larger-size Fe-rich particles are observed to undergo damage at an earlier stage, and consequently, affect the strain localization characteristics the most. In contrast, η precipitates are found to be most resistant to particle damage, followed by θ precipitates. Higher stresses inside strain localization bands, caused increased void damage initiation and growth of η and θ precipitates. Overall, particle fracture is observed to be marginally higher compared to particle decohesion, irrespective of the particle type.

Numerical modelling of the process chain for aluminium Tailored Heat-Treated Profiles

Lightweight construction in modern car design leads to an increased usage of various aluminium semi-finished products. Besides sheet material, aluminium extrusion profiles are frequently used due to their high stiffness and variety of possible cross-sections. However, similar to sheet material, aluminium profiles exhibit limited formability in comparison to mild steel materials. One possibility to increase the forming limits of precipitation hardened aluminium alloys is the so-called Tailored Heat Treatment technology. By a local short-term heat treatment, the material is softened and the material flow can be controlled to reduce stresses in critical forming zones. The purposeful definition of the heat treatment zones is mandatory to improve the forming results. Therefore, numerical methods are necessary. In this investigation, a numerical process chain is presented. It combines the thermo-mechanical simulation of a local laser heat treatment with a subsequent bending process of the heat-treated profile using the alloy EN AW-6082. The temperature distribution, mechanical properties, and finally, the bending result of the numerical model are validated by experimental tests.

Optimization of squeeze casting process parameters for the production of Al composite reinforced with bone powder

Al6061 alloy is most commonly used in automotive, marine, and aerospace applications to reduce weight and improve the strength of the composite. Al6061 alloy is a precipitation-hardened aluminium alloy used as a matrix material. Beef bone is a bio-waste which pollutes the environment and the people who live in the vicinity of its manufacturing and disposal sites. Bio-waste has been used in a variety of ways by researchers in recent years, including activated carbon, water purification, reinforcement in composites, fillers, medicines, food products and additives etc. Recycled beef bones that had been abandoned as waste were collected, cleaned, and ground into a fine powder with a particle size ranges between 5 and 50 µm and used as reinforcement to produce the Al composite. Because, beef bone has good tensile and compression strength and is light in weight, which helps improve the strength without much increase in cost of the Al composite. The aluminium composite are fabricated using squeeze casting process and the design of experiment based on Taguchi design are imposed to produce the high quality Al composite. The aluminium composite is fabricated and nine samples were successfully obtained for testing and analysis. The prepared substrates are analysed for hardness and tensile strength. Based on the experimental run the optimized process parameter conditions are found also regression equation is provided for the design. The optimized process parameters are found for melt temperature, squeeze pressure, reinforcement percentage, stirring speed as 700 °C, 100 MPa, 5%, 600 rpm respectively. Also, the highest contribution for improving the strength of the material is percentage of reinforcement.

Preparation of Nanosize Bone Powder from Waste and Development of Al Composite through Squeeze Casting Process

Al6061 alloy is most commonly used in automotive, marine, and aerospace applications to lighten the composite and increase its strength. Al6061 alloy is a precipitation-hardened aluminum alloy used as a matrix material. Beef bone is a biowaste that has polluted the environment and the people who live in the vicinity of its manufacturing and disposal sites. Biowaste has been used in a variety of ways by researchers in recent years, including activated carbon, water purification, reinforcement in composites, fillers, additives, etc. Beef bones that had been abandoned as waste were collected, cleaned, and grounded into a fine powder with a particle size of 50–100 nm and used as reinforcement. Squeeze casting process is used to create the newly created aluminum composite (Al6061 + 0%, 5%, 10% of bone powder). The aluminum composite was fabricated and three samples were successfully obtained for further testing and analysis. The prepared Al composites with nanopowder reinforcement are analyzed for surface morphology, elemental identification, hardness, porosity, tensile strength, and compression strength. The percentage of porosity in the composite is improved by 36.7% when compared to the Al6061 alloy. Similarly, the tensile strength of the produced composite is increased to 5.59%. A significant improvement is observed in the wear resistance and hardness of the composite as 54.55% and 48.65%, respectively.

Experimental Study of Steel-Aluminum Joints Made by RSW with Insert Element and Adhesive Bonding.

This work focuses on joining steel to aluminum alloy using a novel method of joining by resistance spot welding with an insert element based on anticorrosive steel in combination with adhesive bonding. The method aims to reduce the formation of brittle intermetallic compounds by using short welding times and a different chemical composition of the insert element. In the experiment, deep-drawing low-carbon steel, HSLA zinc-coated steel and precipitation-hardened aluminum alloy 6082 T6 were used. Two types of adhesives-one based on rubber and the other based on epoxy resin-were used for adhesive bonding, while the surfaces of the materials joined were treated with a unique adhesion-improving agent based on organosilanes. The surface treatment improved the chemical bonding between the substrate and adhesive. It was proved, that the use of an insert element in combination with adhesive bonding is only relevant for those adhesives that have a load capacity just below the yield strength of the substrates. For bonded joints with higher load capacities, plastic deformation of the substrates occurs, which is unacceptable, and thus, the overall contribution of the insert element to the load capacity of the joint becomes negligible. The results also show that the combination of the resistance spot welding of the insert element and adhesive bonding facilitates the joining process of galvanized and nongalvanized steels with aluminum alloys and suppresses the effect of brittle intermetallic phases by minimizing the joining area and welding time. It is possible to use the synergistic effect of insert element welding and adhesive bonding to achieve increased energy absorption of the joint under stress.

Integrated lubrication and quenching using a volatile medium and additive manufactured die in hot stamping of precipitation hardening aluminum alloy

To achieve lubrication and quenching during hot stamping of aluminum alloys (AAs), a combination of volatile medium (liquid CO2) and additive manufactured (AMed) die is suggested. The liquid CO2 as a lubricant and coolant is directly applied to the heated AA blank through the AMed die with confusor microholes. While the continuously supplied liquid CO2 reduces the friction between the heated AA blank and AMed die, the cooling rate of the liquid CO2 successfully induces the status of solid solution treatment in the formed blank for a following artificial aging process.

Разработка и сертификация летной годности современной ответственной детали корпуса переключателя для аэрокосмических систем, изготовленной из сплава AlSi10Mg с помощью аддитивной технологии

Aerospace applications can benefit from additive manufacturing (AM), which is highly advantageous for prototyping and rapid manufacturing. It also offers cost and weight savings, as well as integrated design capabilities. As of now, there are only a few AM standards available, many materials and equipment are involved, resulting in many variables that hinder certification and adoption. As a result, nonstandard testing is making AM in the airborne materials less appealing due to its costly and time-consuming nature. The main objective of this work is to manufacture the Selector Valve Body parts of military and civil aircraft through Laser Powder Bed Fusion (LPBF) process using AlSi10Mg powder. Further, this paper has been carried out the metallurgical properties, non-destructive and destructive testing as well as the clear explanation about the certification procedures. Moreover, this underscores the need for the developing guidelines and standards that cover all aspects of manufacturing from design to manufacturing to operation. A comprehensive analysis from liquid penetration test shows defects are within the permissible level. In addition, it exhibits higher yield strength, ultimate strength, and elongation of (259±4), (323±4) MPa, and (12.5±1.5) % respectively, along with factual evidence that the precipitation hardened AlSi10Mg indigenously developed and produced is equal in properties to the equivalent precipitation hardening aluminium alloys produced by internationally renowned manufacturers.

Thermo-mechanical gradation of precipitation-hardenable aluminum alloy AA7075 by differential cooling

The present work investigates the effect of the coupled thermo-mechanical phenomena that occur when applying differential cooling technology by heated and cooled forming tool segments established in functional gradation by press hardening of high strength steel to precipitation-hardenable aluminum alloy AA7075. This application aims at creating graded mechanical properties within one part by a distribution of tailored microstructures. The distribution of the detected precipitations after aging presumably influenced by the spatial variation of the contact cooling rate prior to aging is correlated to the measured sigmoidal hardness profile. Different types and morphologies of precipitates are observed at characteristic positions of the part. The formation of fine and uniformly distributed precipitates at the zones with hardness values of 180 HV is associated to the high cooling rate by low tool segment temperatures. At the same time, coarse and lath-shaped particles are detected at regions with a low hardness value of 123 HV attributed to the lower cooling rate at heated tool segments.

Potentiodynamic Corrosion Behavior and Microstructural Characteristics of Pulsed CMT-Welded AA2014-T6 Aluminium Alloy Joints: Effect of PWHT

AA2014-T6 is an Al-Cu-Mg-based precipitation-hardened aluminium alloy widely used in aerospace due to its high strength to weight ratio. This alloy is joined by a pulsed cold metal transfer (PCMT) arc welding process to overcome the high heat input related problems in gas metal arc welding (GMAW) such as a coarser dendritic structure in the fusion zone (FZ), wider heat affected zone (HAZ), solidification and HAZ liquation cracking, softening in HAZ, and poor corrosion resistance of welded joints in salt environment. The joints were subjected to PWHT of artificial aging (AA), solution treatment (ST), and solution treatment + aging (STA) conditions. The corrosion rate was determined using a potentiodynamic corrosion test in a solution of 3.56 wt.% NaCl with pH values of 4, 7, and 11. Results disclosed that the PCMT joints subjected to the potentiodynamic corrosion test in NaCl solution of pH-4, pH-7, and pH-11 disclosed very low, moderate, and extremely high pitting corrosion, respectively. The corrosion resistance of ST joints was improved by 53.34%, 15%, and 15.12% in pH-4, pH-7, and pH-11 NaCl solution compared to as-welded joints. The pitting potential of ST joints is comparable to BM. The BM showed the pitting potential of −175, −450, and −550 mV in pH-4, pH-7, and pH-11 NaCl solution. The ST joints showed 75.29%, 29.16%, and 27.85% lower corrosion potential compared to STA joints in pH-4, pH-7, and pH-11 NaCl solution, respectively. The ST joints disclosed the lower pitting potential of −105, −425, and −505 mV in pH-4, pH-7, and pH-11 NaCl solution, respectively, whereas the STA joints revealed greater pitting potential of −425, −600, and −700 mV in pH-4, pH-7, and pH-11 NaCl solution, respectively. The superior corrosion resistance of ST joints compared to AA and STA joints is attributed to the dissolution of precipitates in Al solid solution resulting in a lower potential difference in FZ. This minimizes the preferential sites for pitting corrosion to occur.

Novel fast-aging process for Al–Zn–Mg–Cu alloy sheets and its micro-mechanisms

The strength and aging efficiency of precipitation-hardened aluminum alloys are always difficult to be obtained simultaneously. To address this issue, a novel fast-aging process, that is, a two-step aging coupled deformation process, was proposed. The influence of fast-aging parameters on the mechanical behavior of Al–Zn–Mg–Cu alloy was studied, and it was found that secondary aging, pre-aging, and deformation have a major effect, an auxiliary effect, and a coordinating effect, respectively, on the strength of aluminum alloys. Compared to traditional peak strength aging process of the T6 condition, the tensile strengths of the material are improved by 10 MPa (∼1.99%), and the aging time reduced by 89.58%. The continuous growth conditions of the precipitates throughout fast aging were analyzed in detail, and a competitive mechanism for the nucleation and growth of the precipitates in the matrix and on dislocations during secondary aging was proposed. Subsequently, the mechanisms were verified using differential scanning calorimetry (DSC) testing and transmission electron microscopy (TEM) observations.

Predicting Flow Stress Behavior of an AA7075 Alloy Using Machine Learning Methods

The present work focuses on the prediction of the hot deformation behavior of thermo-mechanically processed precipitation hardenable aluminum alloy AA7075. The data considered focus on a novel hot forming process at different tool temperatures ranging from 24∘C to 350∘C to set different cooling rates after solution heat-treatment. Isothermal uniaxial tensile tests in the temperature range of 200∘C to 400∘C and at strain rates ranging from 0.001 s−1 to 0.1 s−1 were carried out on four different material conditions. The present paper mainly focuses on a comparative study of modeling techniques based on Machine Learning (ML) and the Zerilli–Armstrong model (Z–A) as reference. Related work focuses on predicting single data points of the curves that the model was trained on. Due to the way data were split with respect to training and testing data, it is possible to predict entire stress–strain curves. The model allows to decrease the number of required laboratory experiments, eventually saving costs and time in future experiments. While all investigated ML methods showed a higher performance than the Z–A model, the extreme Gradient Boosting model (XGB) showed superior results, i.e., the highest error reduction of 91% with respect to the Mean Squared Error.

Electrochemical corrosion of AA6061-AA7075 double sided FSW joints prepared with and without secondary heating

The present study aims to evaluate corrosion behavior of different zones in the double-sided dissimilar friction stir weld between precipitation hardening aluminum alloys AA6061-T6 and AA7075-T651 of 12.7 mm thickness obtained without and with employing secondary/additional heating. Each specific zone of the welds is tested for corrosion potential, corrosion current and impedance spectroscopy. The stir zone formed is more corrosion resistive than AA7075 but less in comparison to AA6061. The corrosion resistivity of AA7075 dominated region increases significantly on the application of secondary heating. The increase is attributed to the disintegration of large corrosion susceptible precipitates due to intense mixing and stirring facilitated at elevated temperature with the application of additional heating. Although, AA6061 experienced trivial decrease in corrosion resistance as high working temperature resulted in increased grain boundary along with high misorientation angle. The scanning electron microscopic images and elemental line scan at corroded stir zone identified AA7075 as the sacrificed alloy due to galvanic coupling with AA6061 at macroscopic scale and dissolution of Mg/Si at microscopic scale. The regions with higher percentage of high angle grain boundaries observed to undergo faster corrosion rates. The heat produced in second pass left annealing effect on prior welded region wherein lower microhardness is noted. • Corrosion resistance of SZ in AA6061-AA7075 DS-FSW joints is enhanced compared to AA7075 while reduced compared to AA6061. • HAZ and TMAZ on RS (AA7075) showed significantly increased corrosion resistance employing secondary heating. • Breakdown of corrosion sensitive intermetallic helped in increasing corrosion resistance. • Slight drop in corrosion resistance of AA6061 observed after secondary heating as increased fraction of HAGBs promoted IGC.

On the elimination of solidification cracks in fusion welding of Al7075 by TiC-nanoparticle enhanced filler metal

Solidification cracks in fusion welding of high strength and precipitation hardened aluminum alloys have been a major challenge for many years. In this research, the weldability of 3-mm thick Al7075 sheets in fusion arc welding was investigated. Welding was conducted with (heterogeneously) and without (autogenously) TiC-nanoparticle enhanced Al7075 filler metal. Results show that the nanoparticles were effective in eliminating welding solidification cracks completely. Two mechanisms are proposed: (1) TiC nanoparticles act as nucleants in the early stage of solidification to alter the microstructure from dendritic to equiaxed and to refine the grains; (2) TiC-nanoparticles act as nucleants in the late stage of solidification to change the shape of eutectic precipitates from continuous to discontinuous and to promote the formation of the Al-Cu-Mg phase at the expense of the deleterious Mg(Cu,Zn)2 (η) phase. Tensile mechanical properties of autogenous weld could not be obtained due to large solidification cracks. In contrast, the heterogenous joint showed relatively good tensile strength and ductility that, however, were slightly lower compared to unwelded Al7075. This was directly linked to the high amount of porosity in the fusion zone due to the use of non-optimal welding parameters adopted in this study to promote solidification cracking for better comparative study and investigation of effects of nanoparticles.