Alloy Joints Research Articles

A novel approach for the weld defect analysis of friction stir welded AA 6061-T6-AA 5052-H32 dissimilar aluminum alloy joints

This study presents a novel approach for weld defect analysis and characterization in friction stir welding (FSW) of AA 6061-T6 and AA 5052-H32 dissimilar alloys, aiming to advance the understanding of defect dynamics and enhance the overall performance and reliability of weld joints. So, the primary goal of this research was to accomplish the efficient joining of dissimilar aluminum alloys with minimal defects and to advance the understanding of joint characteristics through a holistic strategy incorporating both destructive and non-destructive testing (NDT) methodologies. Grey relational analysis was utilized to select significant experimental levels, guiding the selection of suitable specimens for NDT. A regression analysis was performed between input parameters and output responses, and a moderate fit was achieved. For NDT analysis, a micro-CT scanner was employed to identify and quantify tunnel defects, encompassing height, width, and porosity volume. Finally, controlled parametric variation experiments were conducted by varying the input parameters to optimize plastic deformation and heat generation, significantly reducing tunnel defects through incremental dwell time variation. The findings offer valuable insights into defect minimization and parameter optimization, advancing the efficacy and precision of FSW for dissimilar aluminum alloy joints, with implications for broader industrial applications.

Discrete Prediction of Grain Evolution in Solid-State Welding of Ti<sub>6</sub>Al<sub>4</sub>- V Alloy

Titanium (Ti) alloys, known for their high strength and low weight, are essential in aircraft and aerospace applications. This study focuses on friction spot welding as an innovative, efficient process that creates robust Ti alloys joints while minimizing the carbon footprint. The research aims to develop a cellular automata (CA) model to analyze grain evolution during the friction stir spot welding of Ti6Al4V alloy. The methodology involved simulating the welding process at rotational speeds ranging from 800 to 1,200 rpm using a complex curved-thread shoulder. The CA model incorporated both deterministic and probabilistic approaches to capture the dynamic recrystallization (DRX) behavior. Grain nucleation and growth were modeled based on dislocation density, allowing for an in-depth assessment of the alloy's microstructural changes driven by hardening and softening mechanisms. Validation was performed by comparing the model's predictions with experimental measurements of temperature and grain size. The findings indicate that heat and deformation during welding significantly influence grain size evolution, enhancing the understanding of microstructural behavior in high-strength titanium joints. This work contributes valuable insights into optimizing welding techniques for titanium alloys in aerospace engineering.

High-strength heterostructure joint of 6063Al alloys manufactured by ultrasonic-assisted TLP bonding using an Zn/Mg/Zn composite interlayer

High-strength heterostructure joint of 6063Al alloys manufactured by ultrasonic-assisted TLP bonding using an Zn/Mg/Zn composite interlayer

Mixed-mode failure of adhesively bonded CFRP and iron-based shape memory alloy joints: Experiments and modeling

Mixed-mode failure of adhesively bonded CFRP and iron-based shape memory alloy joints: Experiments and modeling

Microstructure and mechanical properties of SiC ceramics and Kovar alloy joints brazed with AgCuInTi and AgCuInTi + B composite fillers

Microstructure and mechanical properties of SiC ceramics and Kovar alloy joints brazed with AgCuInTi and AgCuInTi + B composite fillers

Effect of beam oscillating frequency on microstructure and mechanical properties of Ti6Al4V alloy joints of unequal thickness

Effect of beam oscillating frequency on microstructure and mechanical properties of Ti6Al4V alloy joints of unequal thickness

The Fatigue Behavior of TC4 and Ti60 Dissimilar Titanium Alloy Joints Welded by Electron Beam

During use, titanium alloy structural components may experience sudden overloads or occasional loads, which can reduce their fatigue life and accelerate structural failure. To study the fatigue behavior of TC4/Ti60 joints, this paper uses electron beam welding technology to obtain TC4/Ti60 dissimilar joints. The results show that the microstructure changes during the welding process, with the weld zone being relatively uniform, primarily consisting of coarse α′ phase. The near heat-affected zone on the TC4 side consists of α′, while on the Ti60 side, in addition to the α′ phase, there is a small amount of residual α phase. Fatigue tests reveal that as the pre-deformation increases, the fatigue life gradually decreases. During the early stages of fatigue, the joint exhibits cyclic hardening, which transitions to cyclic softening as the test progresses, ultimately leading to failure. Fatigue fracture analysis reveals that all fatigue samples failed on the TC4 side, with no failure observed in the weld zone. This is likely due to the presence of martensite, which gives the weld zone higher strength than the TC4 base materials. Additionally, fatigue cracks initiated from surface or near-surface defects, with ductile fractures being predominant.

Effect of Zr Content on the Microstructure and Properties of TC4 Titanium Alloy Joints Brazed with TiZrCuNi Brazing Paste

Effect of Zr Content on the Microstructure and Properties of TC4 Titanium Alloy Joints Brazed with TiZrCuNi Brazing Paste

Effect of Process Parameters in Submerged Friction Stir Welding to Improve the Corrosion Resistance of Aluminum Alloy (AA7075)-Experimental and Mathematical Approach

The present work pertains to an experimental and mathematical approach to the optimisation of the corrosion properties of AA7075-T6 Aluminum alloy welds. Friction Stir Welding (FSW) in a submerged water condition, was carried out on a vertical lathe machine to make a welded joint of aluminium alloy while the process parameters were varied to determine a combination that gives an optimum condition with improved corrosion resistance. The process parameters, namely tool rotational speed (rpm), transverse speed (mm/min) and axial force (kN) have a pivotal role in determining the microstructural and corrosion resistance in the welded joint region. The work is to develop a mathematical model that can be referenced as an optimum corrosion resistance property of a submerged friction stir welded aluminium alloy AA7075-T6 joint through optimisation of process parameters. The experimental data was statistically analysed and the response surface methodology approach enabled the development of the optimised mathematical model that predicts the optimised corrosion resistance of AA7075. The Minitab software was used to obtain a mathematical model that is used to predict the optimum corrosion resistance of AA7075 and optimised values. Finally, the significance of the developed mathematical model was tested through the Analysis of Variance (ANOVA), which showed that tool rotational speed has a great influence on the corrosion resistance rate of the submerged friction stir welded joint. Major Findings: 1. The corrosion resistance decreases with an increase in the tool rotational speed and welding speed. 2. The submerged friction stir welded joint has better corrosion resistance properties when compared to joints made on base metal. 3. A mathematical regression model that predicts the corrosion resistance of SFSW joint, an AA7075 aluminium alloy joint, was developed with a confidence level of above 95%.

Modified Humphreys’ Model-Based Investigation of the Mechanism of Abnormal Grain Growth in Friction-Stir Welded Joints in A356 Aluminum Alloy

Modified Humphreys’ Model-Based Investigation of the Mechanism of Abnormal Grain Growth in Friction-Stir Welded Joints in A356 Aluminum Alloy

Influence of axial load on structure and strength of a heterogeneous joint of titanium alloy Ti-6Al-4V and aluminum alloy Al-6Zn-2Mg-2Cu formed by friction stir welding

Influence of axial load on structure and strength of a heterogeneous joint of titanium alloy Ti-6Al-4V and aluminum alloy Al-6Zn-2Mg-2Cu formed by friction stir welding

Impact of tool rotation speed on boundary structure and properties of AA7075 aluminum alloy and Grade 5 titanium alloy joints during friction stir welding

Impact of tool rotation speed on boundary structure and properties of AA7075 aluminum alloy and Grade 5 titanium alloy joints during friction stir welding

Optimization of FSW input parameters for dissimilar butt-welded joints of Al6061-AZ31 alloys by GRA

In this paper, the optimization of Friction Stir Welding (FSW) parameters used to produce dissimilar non-ferrous butt joints of Al6061 and AZ31 alloys is investigated carefully. FSW parameters including tool rotation speeds (TRS) ranging between 700–1100 rpm, traverse speed (TS) 40–80 mm/min, and axial load (LA) 7–11 KN are considered for finding suitable FSW parameters. The experiments are carried out at different combinations of FSW parameters and the results are measured using respective equipment. The L18 orthogonal array of Taguchi design of experiments is adapted for Grey relation analysis (GRA) multi-objective optimization aiming for high tensile strength and less wear rate with measured responses. Based on grey relational grade, TRS, TS, and axial load of 1100 rpm, 60 mm/min, 9KN are found to best suitable FSW parameters with reasonable tensile strength of 132.43 MPa, microhardness of 70.4 Hv, and lower wear rate of 5.156 mm3/m, respectively. The confirmatory test has been performed to verify the finding of the optimization study with a maximum error percentage of 2%. Furthermore, the corrosion analysis has also been performed for the produced FSW butt joint at a suitable parametric combination. Corrosion behavior is improved due to equiaxed grain distribution and formed hard Mg2Si precipitates that reduce the differential dissolution effect when embedded in Al matrix. It signifies the improvement in chemical inertness in application to extreme temperature environments.

Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al-Mg-Si-Cu alloy joint

Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al-Mg-Si-Cu alloy joint

Study on Microstructures of tungsten-based high-density alloy laser welding-brazing joint

Abstract The microstructure of tungsten-based high-density alloy laser fusion brazed joints was characterized by using optical microscopy, scanning electron microscopy, and X-ray diffractometer in this work. The results indicate that the laser fusion brazing joint includes a fusion welding joint and brazing joint; The weld seam consists of gray α-Ag, black β-Cu, and detached particles of tungsten alloy; β-Cu is distributed in the α-Ag substrate with blocky, rod, and strip morphology, and the layered α-Ag and β-Cu can be seen in some areas. The results reveal that the dominant intermetallic compound in the fusion zone is W particles, γ- (Fe, Ni), and FeNi3 intermetallic compounds. The dominant intermetallic compounds in the brazing seam are α-Ag and β-Cu. There is a compound-type interface in the laser fusion brazing joint of tungsten-based high-density alloy, and the intermetallic phase in the interface is FeZn7.

Effect of pre- and post-weld heat treatments on the microstructure and mechanical properties of the rotatory friction welded martensitic steel-soft magnetic alloy joints

Effect of pre- and post-weld heat treatments on the microstructure and mechanical properties of the rotatory friction welded martensitic steel-soft magnetic alloy joints

Interface bonding behavior and strengthening-failure analysis of 2219 aluminum alloy joint produced by vacuum hot-compression bonding

Interface bonding behavior and strengthening-failure analysis of 2219 aluminum alloy joint produced by vacuum hot-compression bonding

Microstructural evolution of sapphire/Kovar alloy joints brazed with Ag–Cu-Ti filler

Microstructural evolution of sapphire/Kovar alloy joints brazed with Ag–Cu-Ti filler

The Behavior of Dissimilar Welded Joint of Alloy 617/P92 Steel at High Temperatures

The Behavior of Dissimilar Welded Joint of Alloy 617/P92 Steel at High Temperatures

Formation of al-zn-cu-mg alloy joint structure under friction stir welding with additional liquid cooling and subsequent artificial aging

Formation of al-zn-cu-mg alloy joint structure under friction stir welding with additional liquid cooling and subsequent artificial aging