Joining Aluminum Alloy Research Articles

Data Mining and Visualization of High-Dimensional ICME Data for Additive Manufacturing

Integrated computational materials engineering (ICME) methods combining CALPHAD with process-based simulations can produce rich, high-dimensional data for alloy and process design. In ICME methods for metallurgical applications, the visualization and interpretation of such high-dimensional data has previously been through heat maps represented in 2 or 3 dimensions. While such an approach is ideal when one variable is varied at a time, in the case of high-dimensional data with multiple variables varied simultaneously, as is the case in additive manufacturing, interpreting the trends through two- or three-dimensional heat maps becomes challenging. Here, we propose a strategy of mixed visual data mining and quantitative analysis for high-dimensional metallurgical and process data using high-throughput thermodynamic calculations. Two case studies show the application of the proposed approach. The first case study investigated the effects of feedstock chemistry on the $$\delta$$ ferrite formation in 316L stainless steel powders used for binder jet additive manufacturing. The second case study linked Scheil–Gulliver calculations to a process model for dissimilar joining of aluminum alloys 5356 and 6111 during laser hot-wire additive manufacturing. Both cases contained thousands of calculated data points, showcasing the utility of visual data analysis through parallel coordinate plotting, Pearson correlation coefficient matrices, and scatter matrices compared to traditional process maps. These visualization techniques can be extended to many additive manufacturing problems to capture process–structure–property relationships for additively manufactured components.

Static strength analysis and experimental research of clinched joints by two-stroke flattening clinching method

Clinching technologies are increasingly used to join sheet materials in manufacturing, especially in automotive lightweight applications. However, clinched joints have a weak static strength and high protuberance, which influence the application of the clinching technology. In order to improve the static strength and decrease the protuberance high of clinched joint, a new method to join aluminum alloy sheet materials with two-stroke flattening clinching (TFC) was investigated in this paper. The tension-shear strength, cross-tension strength, energy absorption, and failure modes of clinched joint and TFC joint were investigated. The stiffness (K) of the joints under different experimental tests was also studied. The results indicated that the mechanical behaviors of the joints were optimal when the forming force was 35 kN. The maximum cross-tension and tension-shear strength of TFC joint were increased by 514 N and 1145 N on average compared with the initial clinched joint. The main failure modes of the joints were the neck fracture mode under the tension-shearing and cross-tension test.

Mechanical and Microstructural Evolution of Friction stir welded joint of AA2014 alloys

The solidification cracking phenomenon restricts the use of fusion welding process to join aluminum and its alloy. Friction stir welding (FSW) process can be used in joining of aluminium alloys which is not or less susceptible to form welded voids, induced distortions, solidification cracking. In the present work an investigation of mechanical and microstructural changes after FSW is presented during the similar joining of AA2014 aluminium alloys. The influences of tool geometry during FSW is analysed and compared among the joint made by triangular, pedal and pentagonal pin. Based on the obtained mechanical properties of the joint metallurgical investigation is performed. Optical micrographs are used to reveal the phases present in the fusion zone. EBSD investigation of the selected sample is done to analyse the mis-orientaion angle and grain size etc. Pedal pin profile tool exhibit better mechanical properties in comparison to pentagonal pin and triangular pin. Obtained ultimate tensile strength and percentage elongation are 345MPa and 13.5 % respectively. Micro-hardness and impact energy are obtained as 125HV0.2 and 4.6 J of F pedal sample. Obtained joint efficiency of Fpedal sample is 74%, which is higher among joint efficiency of Fpentagonal and Ftringular samples.

Numerical and experimental studies on friction stir welding of 6061-T6 AA with Al2O3 powder particle reinforcement

The present study focuses on the joining of aluminium alloy (6061-T6) with Al2O3 powder particle by friction stir welding (FSW) technique. The Al2O3 nanoparticles are added to the aluminium matrix by making the slot on the abutting interface of each plate and filling the gap with nanoparticles and clamping the samples tightly. Nanoparticles were added to the aluminium matrix for refining the grain size in the nugget zone (NZ) and heat-affected zone (HAZ). The microstructure and mechanical properties of the welded samples with nanoparticles are elaborated in detail. Addition of Al2O3 nanoparticles with 6061-T6 AA refines the grain size, and remarkable improvement in the mechanical properties of the joint in comparison to the same welding parameter welded samples without nanoparticles. The welding was done with a rotational speed of 800 rpm and a transverse speed of 55 mm/min. A level set (volume fraction) method was used to elaborate the mixing of powder particles with aluminium matrix. Numerical analysis of heat generation and material flow of the aluminium-based nanocomposite FSW was studied.

Detailed characterizations of microstructure evolution, corrosion behavior and mechanical properties of refill friction stir spot welded 2219 aluminum alloy

2.0 mm thick 2219-O (upper plate) and 8.0 mm thick 2219-C10S (lower plate) were successfully fabricated using refill friction stir spot welding (RFSSW), and the microstructure evolution, corrosion behavior and mechanical properties of the joints were investigated. The results indicated that the stir zone (SZ) is characterized by refined and equiaxed grains due to dynamic recrystallization, whose grain size gradually increases, and the texture intensity decreases with the increase of the distance from the upper plate top surface. Tangled dislocations and dislocation cells are observed in the SZ, while rod-like precipitates with 20 nm–100 nm length are found in the base material (BM) of the lower plate. Also, numerous Al 2 Cu particles are observed in the upper plate BM, while only a few particles are aggregated in the lower plate BM. However, Al 2 Cu particles are fragmented and uniformly distributed in the SZ. The hardness of the upper plate and the lower plate is approximate 50 HV and 160 HV, respectively. The hardness increases gradually from top to bottom of the cross-section. The self-corrosion potential and corrosion current density of the SZ are −0.45 V and 5.62 × 10 −5 A/cm 2 , respectively. In comparison, those of the BM of the upper plate are −0.49 V and 3.16 × 10 −3 A/cm 2 , and those of the lower plate BM are −0.68 V and 7.94 × 10 −3 A/cm 2 . The electrochemical experiment indicated that the SZ presents excellent corrosion resistance, followed by upper plate BM and then lower plate BM. The corroded area has mainly occurred at the lower plate BM when the joint cross-section is immersed in the EXCO solution for one hour. However, upper and lower plate BMs are eroded seriously when the immersion time increases to two hours. Nevertheless, no obvious corrosion can be observed in the SZ. The mechanical analysis indicated that the tensile load decreases from 7.25 to 4.10 kN, and the tear load decreases from 3.20 to 1.78 kN after being immersed in the 3.5% NaCl solution for 48 h. • Refill friction stir spot welding technology has great advantages in joining aluminum alloys with unequal thickness. • The grains above the lap interface are equiaxed, while those below the lap interface are elongated. • The hardness increases gradually from the top to the bottom of the joint cross-section. • The corrosion resistance of SZ is the best, followed by upper plate BM and lower plate BM. • The tensile force decreases from 7.25 to 4.10 kN, and the tear force decreases from 3.20 to 1.78 kN after being immersed for 48 h.

Microstructural characterization of Friction stir assisted laminated lap welding of AA6063 sheets

Friction stir welding is a pioneering new technique for solid-state joining of Aluminium alloys, which also further strengthens the mechanical and microstructural properties of the base metal. Laminated lap welding on AA6063 sheets was performed using a stainless-steel tool with a square cross-section pin. The sample thus obtained was examined for their microstructural and hardness properties, and was characterized accordingly. Equiaxed grain structures are obtained commonly in friction stir welded samples. A refined grain size of ∼ 15 μm was observed in the microstructural characterization. The hardness profile depends on the degree of grain refinement as explained by the Hall-Petch effect. The microhardness was observed to be 135 % of the base metal hardness. The study has hinted towards the improvement of properties after friction stir lap welding and serves as a base for multilayer solid-state joining as a future prospect.

Fatigue characteristic in non- combustible magnesium alloy dissimilar materials joint with different combination of upper plate / lower plate materials

Using non-combustible magnesium alloys for structural materials contributes to weight reduction in transportation equipment. Therefore, appropriate joining method for non-combustible magnesium alloy with high reliability is necessary. Self-Piercing Rivet (SPR) joint has been widely applied to joining aluminum alloys and is suitable for joining of dissimilar metals. In this study, SPR joint was applied to a non-combustible magnesium alloy AX41, and fatigue strength properties of AX41 similar material joint and dissimilar materials joints with AA6061 and SPCC were evaluated. The dissimilar material joints exhibited higher fatigue strength compared to AX41 similar material joint. Depending on the combination of the upper and lower plate materials, cracks may occur during the joining process, and fatigue properties may be affected. Regardless of the plate materials combination, stiffness of a plate is considered to have a significant effect on fatigue strength of SPR joint because deformation of upper and lower plates has an effect on fatigue mechanism.

Effect of tool rotational speed on the friction stir welded aluminum alloys: A review

In contemporary world, leading industries such as automotive and aviation are using aluminium alloys due to its high strength to weight ratio. Conventional welding methods such as fusion arc welding causes solidification and liquid cracking in aluminium alloys. Friction Stir Welding (FSW), a solid state process has gained stupendous reputation in welding industry by successfully joining aluminium alloys with no obvious defects. The process parameters such as tool rotational speed, tool traverse speed and tool geometry plays a significant role in obtaining defect free welds and in increasing the joint efficiency. Tool rotational speed greatly influences the material movement and heat generation in FSW. This paper highlights the effect of rotational speed on mechanical and microstructural properties of the various aluminium alloys. The role of tool rotational speed in elimination of defects such as tunnel and kissing bond has also been discussed.

Various welding processes for joining aluminium alloy with steel: Effect of process parameters and observations–a review

The versatile aluminium alloys and steel are being used in automotive engines (exhaust systems), pressure vessels (flanges), turbine rotors, boilers (bonnet) and in many applications. The collective effect of these two metals created a revolution and are being utilized in most of the sectors wherein joining of these two dissimilar materials are always a major challenge faced by the manufacturers. Initially, the rivets were widely used for joining dissimilar materials owing to easy installation and flexibility, but the joint interlock fails and sudden ruptures occurred when exposed to higher load. Hence, numerous welding processes like metal inert gas welding, friction stir welding, friction stir spot welding, advanced laser welding, advanced cold metal transfer welding and hybrid welding techniques have been introduced in order to conquer the above problem because of residual stresses, cracks, distortion, and undercuts. Moreover, an appropriate standardization with controlled process inputs is still an uncertainty in joining the dissimilar materials. Hence, a detailed review on joining the dissimilar metals based on aluminium alloy and steel by various welding processes and influence of their parameters on the properties have been summarized in detail which would be a reference for manufacturing industries in the coming decades.

Dissimilar laser spot welding of aluminum alloy to steel in keyhole mode

Laser spot welding was used for the dissimilar joining of aluminum alloy to steel in the keyhole mode. The results showed that the defocusing amount and laser power had significant influence on the weld formation. The aluminum alloy was prone to the formation of welding defects, such as porosity and cracks in the fusion zone, which resulted in an extremely instable welding process and poor joint strength. In order to improve the weld quality, a copper heat sink was placed under the aluminum alloy, which effectively absorbed the heat of the aluminum alloy and reduced the previous reported welding defects. The influence of laser power, defocusing amount, welding time, and shielding gas on the joint characteristics was also investigated. The microstructure analysis showed that a conelike fusion zone and sparsely distributed Fe-Al intermetallic compounds were formed. Hence, a combination of metallurgical bonding and mechanical interlocking was achieved in the laser keyhole spot welds, enhancing the joint mechanical properties. The joint strength of the laser keyhole spot welds reached 620 N/mm, which was comparable to that obtained in resistance spot welds.

Prediction of peak temperature value in friction lap welding of aluminium alloy 7475 and PPS polymer hybrid joint using machine learning approaches

In the automotive and aerospace sectors, vehicle weight has been a major concern for the past decades. Incorporating metal-polymer hybrid structures reduces weight without compromising structural performance. In this work, Friction Lap Welding (FLW) technique was used to join aluminium alloy 7475 with PPS polymer. To conduct the FLW experiments, a design matrix was developed with the help of Response surface methodology. For each experimental run, the peak temperature value was recorded. The possibility of machine learning algorithms for predicting peak temperature during joining has been assessed. The maximum correlation coefficient (i.e., 0.999) and minimum root mean square error (i.e., 0.068) were observed for the support vector machining (SVM) model with the PUK kernel. So, SVM-PUK approach was determined to be the most efficient.

Experimental investigation of tailor welded blanks of dissimilar aluminum alloys

Tailor Welded Blanks (TWBs) are now-a-days being used in many vehicles due to its advantage of reduced vehicle weight. In the decades from year 1990 to 2010, TWBs manufactured of high-strength steel alloys were the focus of the researchers' research. After year 2010 onwards, the focus of automotive industry shifted towards use of aluminum alloys and resulted in more research work related to welding process of aluminum alloys. In this research work, Friction Stir Welding (FSW) is used to join aluminum alloys AA6061-T6 and AA5052-H32. Process parameters of FSW i.e. Spindle Speed (N), Shoulder Dia. (SD) and Feed (f) are optimized by Response Surface Method (RSM) approach. Output parameters like Ultimate Yield Strength (UTS) and % Elongation are considered. Multi-objective optimization by RSM approach suggests that shoulder diameter = 16 mm, spindle speed = 1500 rpm and feed = 40 mm/min are optimum results obtained and when kept at this level will provide UTS in the range of 160 MPa-180 MPa and 10 % to 11 % elongation can be expected for friction-stir-welded blanks.

Optimization of FSW Process Parameters to Yield Maximum Shear Fracture Load of AA2024 Aluminum Alloy Joints

AA2024 Aluminum alloy has predominantly been used for making aircraft engine parts and frames. The normal welding process does not apply to join aluminum alloy. Because Al and its alloy have a low melting point and high thermal conductivity, which can easily lead to porosity and partially melting; as a result, Friction Stir Welding (FSW) has been employed to solve these issues. This work focused on the parameter’s optimization to the conceived maximum strength of AA2024 aluminum alloy. Four major parameters viz., tilt angle, shoulder diameter, welding speed, and rotational speed were selected. The formulation of empirical relationship was made using statistical tool design of experiment, and analysis of variance has been used to check the developed model’s adequacy. Furthermore, the response surface graphs were used to identify the maximum strength and its corresponding FSW parameters. The joint obtained the full power from the experimental results at a tilt angle of 1.5 deg., traverse speed of 15 mm/min, speed of tool 1100 rpm, and diameter of shoulder 24 mm.

Effect of Carbonitriding on Tribomechanical and Corrosion-Resistant Properties of Friction Stir Welded Aluminium 2024 Alloy

Abstract Friction stir welding (FSW) is extensively used to join aluminium alloys components in space and aircraft industries. Al 2024 is a heat-treatable aluminium alloy with copper as the primary alloying element which has good strength and fatigue resistance. This paper investigates the effect of carbonitriding surface modification on the hardness, tensile strength and impact strength of FSW welded Al 2024 joints. The friction stir welding was performed on three different sets of aluminium alloy (Al2024:Al2024, Al2024: carbonitrided-Al2024, carbonitrided-Al2024: carbonitrided-Al2024) at two different tool rotation speed (TRS) and two welding speed using cylindrical pin tool. The carbonitriding pre-treatment of Al-2024 alloy demonstrated significant improvement in the tensile strength, percentage elongation, abrasion wear resistance and corrosion resistance with the sacrifice of impact strength. The maximum tensile strength of all three sets of samples after FSW was recorded in descending order of (i) carbonitrided-Al2024:carbonitrided-Al2024 (ii) Al2024:Carbonitrided-Al2024 and (iii) Al2024:Al2024. The friction stir welded joint of carbonitrided aluminium alloy exhibited best abrasive wear resistant and corrosion resistant properties.

A Review on Laser-Assisted Joining of Aluminium Alloys to Other Metals

Modern industry requires different advanced metallic alloys with specific properties since conventional steels cannot cover all requirements. Aluminium alloys are becoming more popular, due to their low weight, high corrosion resistance, and relatively high strength. They possess respectable electrical conductivity, and their application extends to the energy sector. There is a high demand in joining aluminium alloys with other metals, such as steels, copper, and titanium. The joining of two or more metals is challenging, due to formation of the intermetallic compound (IMC) layer with excessive brittleness. High differences in the thermophysical properties cause distortions, cracking, improper dilution, and numerous weld imperfections, having an adverse effect on strength. Laser beam as a high concentration energy source is an alternative welding method for highly conductive metals, with significant improvement in productivity, compared to conventional joining processes. It may provide lower heat input and reduce the thickness of the IMC layer. The laser beam can be combined with arc-forming hybrid processes for wider control over thermal cycle. Apart from the IMC layer thickness, there are many other factors that have a strong effect on the weld integrity; their optimisation and innovation is a key to successfully delivering high-quality joints.

Dissimilar materials joining of aluminum alloy / carbon fiber reinforced plastic

Dissimilar materials joining of aluminum alloy / carbon fiber reinforced plastic

Effect of Interfacial Intermetallic Compounds Morphology on Mechanical Properties of Laser Brazing of Aluminum to Steel

The paper provides experimental details of the welding and specific examples of welding aluminum welding battery cans and conductive tabs for battery pack manufacture. In this study, we provide experimental details of a process for joining dissimilar materials used in sealing battery parts. A laser brazing technique was used for the lap joining of aluminum alloy and a deep drawing quality stainless steel, with an Al-Si filler metal. These materials are commonly used in battery applications, as materials for the cap plate, tab plate and can. The relationships among the width of the brazed zone, formation of intermetallic compounds (IMCs), shape of the joint interface, and joint strength were systematically investigated with respect to the laser power and filler wire feeding rate. When a low and medium laser power (1.2-2.0 kW) was applied, the joint strength was very low, and fracture occurred across the band-shaped IMC layer. With a further increase in the applied laser power (2.2-2.8 kW), a new needle-like IMC composed of Al13Fe5 with a monoclinic crystal structure was formed, and it penetrated the brazed zone. In addition, the width of the brazed zone increased due to the partial melting of the aluminum. The joint efficiency under a high laser power condition was 70% compared to that of the base material. Fractures occurred alternately along the needle-shaped IMC and filler metal zone. Since the fracture propagated along the needle-like IMCs inside the brazed zone, the peak load was higher than that of the band-shaped IMCs.

Numerical analysis of the effect of heat loss by zinc evaporation on aluminum alloy to hot-dip galvanized steel joints by electrode negative polarity ratio varied AC pulse gas metal arc welding

In joining of aluminum alloy to hot-dip galvanized (GI) steel by arc welding-brazing process, evaporation of zinc (Zn) layer and formation of brittle Fe Al intermetallic compound (IMC) layer can affect the joint quality both thermally and metallurgically. At this point, the alternate current pulse gas metal arc welding (AC pulse GMAW) process is an excellent joining method because of its relatively low heat input to the base metal by controlling the electrode negative polarity (EN) ratio in its current waveform. In this study, a numerical analysis of joining 1.2 mm-thick GI steel to 1.2 mm-thick AA5052 aluminum alloy in the lap configuration using AC pulse GMAW was conducted to determine the effect of the EN ratio and Zn evaporation on joint quality. Based on the finite element method (FEM) 3D heat transfer model, the heat conduction analysis and the estimation of the IMC layer growth at the joint interface were carried out. The calculated results were validated with the corresponding experimental results and demonstrated a fair agreement. The results indicated that the temperature-dependent Zn mass evaporation and the increased EN ratio decrease the heat input to the joint interface. In particular, the heat loss caused by Zn evaporation with its latent heat restricts the growth of the brittle Fe Al IMC layer, which follows a function of temperature variation per unit length and time, by decreasing the heat from the arc to the joint interface. A 7.83 μm-thick IMC layer was obtained at a welding current of 55 A with an EN ratio of 20%, and a sound dissimilar material joint was achieved.

Friction Spot Joining of Aluminum Alloy to Polymer

Friction Spot Joining of Aluminum Alloy to Polymer

Flexural and crashworthiness studies of friction stir welded aluminum alloy pipes

Friction stir welding (FSW), a solid-state joining process, is commonly used to join Aluminum alloys in aerospace, marine, car industry, and numerous industrial applications. Lightweight materials are commonly used in the transport industry to minimize component weight, and thin-walled structures are increasingly being used as energy-absorbing components in the industry. Even though FSW of plates is well established, FSW of pipe is still at the laboratory level. In this work, FSW for 6063 aluminum alloy pipe has been experimented through a novel procedure and it’s flexural and crashworthiness studies are carried out. The attempt of FSW is performed with a unique welding fixture mounted on a traditional milling machine. The crashworthiness test is conducted to analyze the ability of the structure to nullify the life loss during impact and the crash force efficiency of the pipe is identified. It is further analyzed for the flexural test to identify the bending load of welded aluminum alloy pipes. This study also exposes the basic understanding of the FSW procedure and its metallurgical implications of a friction stir welded pipe.