scholarly journals Review of Techniques for Improvement of Softening Behavior of Age-Hardening Aluminum Alloy Welded Joints

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5804
Author(s):  
Jiwen Cheng ◽  
Gang Song ◽  
Xiaosheng Zhang ◽  
Chunbai Liu ◽  
Liming Liu
Keyword(s):  
Aluminum Alloy ◽  
Welded Joints ◽  
Strengthening Mechanism ◽  
Fusion Welding ◽  
Age Hardening ◽  
Main Research ◽  
Softening Mechanism ◽  
Performance Change ◽  
Softening Behavior ◽  
And Performance

The softening phenomenon of age-hardening aluminum alloy-welded joints is severe during conventional fusion welding, which increases the likelihood of stress and strain concentration in the joint during the period of service, significantly reduces the mechanical properties compared to the base metal, and represents an obstacle to the exploration of the potential structural performance. This review paper focuses on an overview of the softening phenomenon. Firstly, the welding softening mechanism and the characteristics of age-hardening aluminum alloys are clarified. Secondly, the current main research methods that can effectively improve joint softening are summarized into three categories: low-heat-input welding, externally assisted cooling during welding, and post-weld treatment. The strengthening mechanism and performance change rule of age-hardening aluminum alloy joints are systematically analyzed. Finally, this paper considers the future development trends of further research on joint softening, and it is expected that interest in this topic will increase.

Constitutive Equation and Dynamic Softening Behavior of 7A55 Aluminum Alloy during Compression at Elevated Temperatures

2017 ◽  
Vol 898 ◽  
pp. 291-299
Author(s):  
Di Feng ◽  
Xin Ming Zhang ◽  
Sheng Dan Liu
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Elevated Temperatures ◽  
Boundary Migration ◽  
Compression Tests ◽  
Softening Mechanism ◽  
Softening Behavior ◽  
Deformation Behaviors

The hot deformation behaviors of 7A55 aluminum alloy were investigated by compression tests at temperatures ranging from 270°C to 450°C and strain rate ranging from 0.1s−1 to 25s−1. Tha rResults show that the flow stress increased with increasing strain rate and decreasing temperature. A two-stage constitutive equation was established and the hot deformation activation energy was 140 kJ/mol. EBSD observations show that the fine and equiaxed grains with the misorientation angle above 15° nucleated at the initial grain boundaries under high temperature and low strain rate conditions. It is concluded that the softening mechanism of 7A55 aluminum alloy is dynamic recovery (DRV), together with a partial dynamic recrystallization (DRX). The nucleation mechanism of DRX could be explained by the strain induced grain boundary migration (SIBM). The DRX softening model was established based on the dislocation density theory finally.

Microstructure and morphology evolution of probeless friction stir spot welded joints of aluminum alloy

2018 ◽  
Vol 252 ◽  
pp. 69-80 ◽  
Author(s):  
W.Y. Li ◽  
Q. Chu ◽  
X.W. Yang ◽  
J.J. Shen ◽  
A. Vairis ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Welded Joints ◽  
Morphology Evolution ◽  
Friction Stir ◽  
Spot Welded

scholarly journals Increasing of the Mechanical Properties of Friction Stir Welded Joints of 6061 Aluminum Alloy by Introducing Alumina Particles

2017 ◽  
Vol 17 (2) ◽  
pp. 29-40 ◽  
Author(s):  
M. A. Tashkandi ◽  
J. A. Al-Jarrah ◽  
M. Ibrahim
Keyword(s):  
Aluminum Alloy ◽  
Base Metal ◽  
Welded Joints ◽  
Volume Fraction ◽  
Welding Process ◽  
Welding Zone ◽  
6061 Aluminum Alloy ◽  
Friction Stir ◽  
Alumina Particles ◽  
Welding Line

AbstractThe main aim of this investigation is to produce a welding joint of higher strength than that of base metals. Composite welded joints were produced by friction stir welding process. 6061 aluminum alloy was used as a base metal and alumina particles added to welding zone to form metal matrix composites. The volume fraction of alumina particles incorporated in this study were 2, 4, 6, 8 and 10 vol% were added on both sides of welding line. Also, the alumina particles were pre-mixed with magnesium particles prior being added to the welding zone. Magnesium particles were used to enhance the bonding between the alumina particles and the matrix of 6061 aluminum alloy. Friction stir welded joints containing alumina particles were successfully obtained and it was observed that the strength of these joints was better than that of base metal. Experimental results showed that incorporating volume fraction of alumina particles up to 6 vol% into the welding zone led to higher strength of the composite welded joints as compared to plain welded joints.

Influence of Stress Concentration on Fatigue Property of Welded Joints of 5083 Aluminum Alloy

2013 ◽  
Vol 456 ◽  
pp. 451-455
Author(s):  
Jun Yang ◽  
Bo Li ◽  
Qiang Jia ◽  
Yuan Xing Li ◽  
Ming Yue Zhang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Welded Joints ◽  
Weld Zone ◽  
Fatigue Property ◽  
Concentration Coefficient ◽  
5083 Aluminum Alloy ◽  
Stress Concentration Coefficient

Fatigue test of the welded joint of 5083 aluminum alloy with smooth and height of specimen and the weld zone than the high test measurement and theoretical stress concentration coefficient calculation, the weld reinforcement effect of stress concentration on the fatigue performance of welded joints. The results show that: Smooth tensile strength of specimens for 264MPa, fatigue strength is 95MPa, the tensile strength of the 36%. Higher tensile strength of specimens for 320MPa, fatigue strength is 70MPa, the tensile strength of the 22%. Higher specimen stress concentration coefficient is 1.64, the stress concentration to the weld toe becomes fatigue initiation source, and reduces the fatigue strength and the fatigue life of welded joints.

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