scholarly journals Effect of Corrosion and Surface Finishing on Fatigue Behavior of Friction Stir Welded EN AW-5754 Aluminum Alloy Using Various Tool Configurations

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3121 ◽  
Author(s):  
Abootorab Baqerzadeh Chehreh ◽  
Michael Grätzel ◽  
Jean Pierre Bergmann ◽  
Frank Walther
Keyword(s):  
Climate Change ◽  
Aluminum Alloy ◽  
Fatigue Behavior ◽  
Salt Spray ◽  
Base Material ◽  
Fatigue Properties ◽  
Surface Finishing ◽  
Friction Stir ◽  
Stationary Shoulder ◽  
Root Surfaces

In this study, fatigue behavior of surface finished and precorroded friction stir welded (FSW) specimens using various tool configurations were comparatively investigated by the load increase method. The FSW using conventional, stationary shoulder and dual-rotational configurations was carried out by a robotized tool setup on 2 mm EN AW-5754 aluminum sheets in butt joint formation. After extraction of the specimens, their weld seam and root surfaces were milled to two different depths of 200 µm and 400 µm to remove the surface and the FSW tool shoulder effects. This surface finishing process was performed to investigate the effect of the surface defects on the fatigue behavior of the FSW EN AW-5754 aluminum alloy sheets. It was found that material removal from the weld and root surfaces of the specimens, increased the fracture stresses of conventional and dual-rotational FSW from 204 to 229 MPa and 196 to 226 MPa, respectively. However, this increase could not be detected in stationary shoulder FSW. Specimens with finished surfaces, which showed superior properties, were used in salt spray and cyclic climate change test to investigate the effect of corrosion on the fatigue behavior of FSW specimens. It was shown that cyclic climate change test reduced the fatigue properties of the base material, conventional, stationary shoulder and dual-rotational FSW approximately 1%–7%. This decrease in the fatigue properties was greater in the case of the salt spray test, which was 7% to 21%.

scholarly journals Fatigue Behavior of Conventional and Stationary Shoulder Friction Stir Welded EN AW-5754 Aluminum Alloy Using Load Increase Method

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1510
Author(s):  
Abootorab Baqerzadeh Chehreh ◽  
Michael Grätzel ◽  
Jean Pierre Bergmann ◽  
Frank Walther
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Strength ◽  
Aluminum Alloys ◽  
Efficient Method ◽  
Fatigue Behavior ◽  
Friction Stir ◽  
Stationary Shoulder ◽  
Aluminum Sheets ◽  
Load Increase ◽  
Weld Seams

The load increase method, which is highly efficient in rapidly identifying the fatigue performance and strength of materials, is used in this study to investigate friction stir welded (FSW) EN AW-5754 aluminum alloys. Previous investigations have demonstrated the accuracy and efficiency of this method compared to Woehler tests. In this study, it is shown that the load increase method is a valid, accurate and efficient method for describing the fatigue behavior of FSW weld seams. The specimen tests were performed on 2 mm thick aluminum sheets using conventional and stationary tool configurations. It is shown that an increase in fatigue strength of the FSW EN AW-5754 aluminum alloys can be achieved by using the stationary shoulder tool configuration rather than the conventional one.

scholarly journals Fatigue Modeling Containing Hardening Particles and Grain Orientation for Aluminum Alloy FSW Joints

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2024 ◽  
Author(s):  
Guoqin Sun ◽  
Yicheng Guo ◽  
Xiuquan Han ◽  
Deguang Shang ◽  
Shujun Chen
Keyword(s):  
Aluminum Alloy ◽  
Grain Orientation ◽  
Base Material ◽  
Correlation Method ◽  
Stress Transfer ◽  
Macroscopic Model ◽  
Fatigue Properties ◽  
Isotropic Hardening ◽  
Stress And Strain ◽  
Friction Stir

The macro-mesoscopic joint fatigue model containing hardening particles and crystal characteristics is established to study the effect of the hardening particles and the grain orientation on fatigue properties of an aluminum alloy friction stir welding (FSW) joint. The macroscopic model is composed of the weld nugget zone, thermo-mechanically affected zone, heat-affected zone, and base material, according to the metallurgical morphology and hardness distribution of the joint. Cyclic stress and strain data are used to determine the material properties. The fatigue parameters used in the calculation of cyclic stresses and strains are obtained with the four-point correlation method. The mesoscopic models of different zones are inserted into the joint macroscopic model as submodules. The models containing the information of hardening particles and grain orientation are established with crystal plasticity theory for the grains and isotropic hardening rule for the hardening particles. The effects of hardening particles and grain orientation on the stress and strain responses are discussed. The simulation results show that high-angle misorientation of adjacent grains hinders the stress transfer. The particle cluster or cracked particles intensify the stress and strain concentrations.

Fatigue Property of Friction Stir Welded Butt Joints for 6156-T6 Aluminum Alloy

2019 ◽  
Vol 960 ◽  
pp. 45-50
Author(s):  
An Chen ◽  
Jun Yang ◽  
Xian Min Chen ◽  
Deng Ke Dong
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Fatigue Behavior ◽  
Fatigue Cracking ◽  
Fatigue Property ◽  
Optical Microscope ◽  
Butt Joint ◽  
Fatigue Properties ◽  
Butt Joints ◽  
Friction Stir

This study was conducted to investigate fatigue behavior of friction stir welding (FSW) butt joints for 6156-T6 aluminum alloy. The detail fatigue rating (DFR) values of 6156-T6 FSW joints is obtained based on statistical analysis of fatigue tests. The micrographs of weld structure were observed by optical microscope (OM), Fatigue fractography was researched under scanning electron microscope (SEM). The results indicate that DFR value of 6156-T6 FSW joints is 153.31MPa. Fatigue property of FSW butt joints is sensitive to the microstructural features, such as nugget zone (NZ), thermo mechanically affected zone (TMAZ) and heat affected zone (HAZ). The hardness distributions of the FSW joints reveal W-shaped profiles. Fractography shows that fatigue cracking is initiated at weak-bonding defects, which are located at the root site of the butt joint. The weak-bonding defects have obvious influence on the fatigue properties of friction stir welding.

Fatigue Behavior of Friction Spot Stir Welding with No-Keyhole of Aluminum Alloy

2014 ◽  
Vol 1052 ◽  
pp. 509-513 ◽  
Author(s):  
Xi Jing Wang ◽  
Xiao Long Wang ◽  
Zhong Ke Zhang ◽  
Lei Wang ◽  
Qing Shan Zhao ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Spot Welding ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Strengthening Phase ◽  
Friction Stir ◽  
Increasing Trend ◽  
Fracture Appearance ◽  
Welding Joints

The fatigue properties of refill friction stir welding joints of 6082-T6 aluminum alloy were completed based on the optimal process parameters. The expression of the fatigue life prediction were obtained in a certain range. The microstructure and fatigue fracture appearance of welding joints were observed and analyzed. And the microhardness of the joints were tested. The results showed that the fatigue crack initiated from the root of the joints between the lower and upper plate, that is the junction of HAZ and TMAZ, and then propagated to fracture along the boundary between the HAZ and the TMAZ. Strengthening phase which was formed of trace elements significantly affected the fatigue properties of spot welding joints. The fatigue life of spot welding joints along with stress intensity factors decrease showed an increasing trend. Fatigue life of spot welding joints emerge an increasing trend along with decreases of the load.

Improvement in Fatigue Strength of Friction Stir Welded Aluminum Alloy Plates by Laser Peening

2014 ◽  
Vol 891-892 ◽  
pp. 969-973 ◽  
Author(s):  
Yuji Sano ◽  
Kiyotaka Masaki ◽  
Keiichi Hirota
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Strength ◽  
Fatigue Testing ◽  
Large Deviation ◽  
Fatigue Cracks ◽  
Weld Zone ◽  
Base Material ◽  
Fatigue Properties ◽  
Laser Peening ◽  
Friction Stir

Plane bending fatigue testing was performed to study the fatigue properties of friction stir welded (FSW) 3 mm thick AA6061-T6 aluminum alloy plates. Fatigue cracks propagated with bends and curves on the specimens, showing large deviation from a linear line. This might be reflecting the material flow and microstructure in the weld zone. The fatigue strength of the unwelded base material (BM) was 110 MPa at 107 cycles and FSW deteriorated it to 90 MPa. However, laser peening (LP) restored the degraded fatigue strength up to 120 MPa which is higher than that of the BM.

Fatigue Behaviour of Friction Stir Welded Steel Joints

2014 ◽  
Vol 891-892 ◽  
pp. 1488-1493 ◽  
Author(s):  
José Azevedo ◽  
Virgínia Infante ◽  
Luisa Quintino ◽  
Jorge dos Santos
Keyword(s):  
Base Material ◽  
Welding Process ◽  
Steel Structures ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Welded Steel ◽  
Shipbuilding Industry ◽  
Friction Stir ◽  
Steel Joints

The development and application of friction stir welding (FSW) technology in steel structures in the shipbuilding industry provide an effective tool of achieving superior joint integrity especially where reliability and damage tolerance are of major concerns. Since the shipbuilding components are inevitably subjected to dynamic or cyclic stresses in services, the fatigue properties of the friction stir welded joints must be properly evaluated to ensure the safety and longevity. This research intends to fulfill a clear knowledge gap that exists nowadays and, as such, it is dedicated to the study of welded steel shipbuilding joints in GL-A36 steel, with 4 mm thick. The fatigue resistance of base material and four plates in as-welded condition (using several different parameters, tools and pre-welding conditions) were investigated. The joints culminate globally with defect-free welds, from which tensile, microhardness, and fatigue analyses were performed. The fatigue tests were carried out with a constant amplitude loading, a stress ratio of R=0.1 and frequency between 100 and 120 Hz. The experimental results show the quality of the welding process applied to steel GL-A36 which is reflected in the mechanical properties of joints tested.

Experimental Study of Stationary Shoulder Friction Stir Welded 7N01-T4 Aluminum Alloy

2016 ◽  
Vol 25 (3) ◽  
pp. 1228-1236 ◽  
Author(s):  
S. D. Ji ◽  
X. C. Meng ◽  
Z. W. Li ◽  
L. Ma ◽  
S. S. Gao
Keyword(s):  
Experimental Study ◽  
Aluminum Alloy ◽  
Friction Stir ◽  
Stationary Shoulder

Microhardness and Microstructural Studies on Underwater Friction Stir Welding of 5052 Aluminum Alloy

2017 ◽  
Author(s):  
Srinivasa Rao Pedapati ◽  
Dhanis Paramaguru ◽  
Mokhtar Awang
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Plate Thickness ◽  
Base Material ◽  
Friction Stir ◽  
Underwater Friction Stir Welding ◽  
Void Area ◽  
Average Size ◽  
Microstructural Studies

As compared to normal Friction Stir Welding (FSW) joints, the Underwater Friction Stir Welding (UFSW) has been reported to be obtainable in consideration of enhancement in mechanical properties. A 5052-Aluminum Alloy welded joints using UFSW method with plate thickness of 6 mm were investigated, in turn to interpret the fundamental justification for enhancement in mechanical properties of material through UFSW. Differences in microstructural features and mechanical properties of the joints were examined and discussed in detail. The results indicate that underwater FSW has reported lower hardness value in the HAZ and higher hardness value in the intermediate of stir zone (SZ). The average hardness value of underwater FSW increases about 53% greater than its base material (BM), while 21% greater than the normal FSW. The maximum micro-hardness value was three times greater than its base material (BM), and the mechanical properties of underwater FSW joint is increased compared to the normal FSW joint. Besides, the evaluated void-area fraction division in the SZ of underwater FSW joint was reduced and about one-third of the base material (BM). The approximately estimated average size of the voids in SZ of underwater FSW also was reduced to as low as 0.00073 mm2, when compared to normal FSW and BM with approximately estimated average voids size of 0.0024 mm2 and 0.0039 mm2, simultaneously.

TEM Characterization of a 7042 Aluminum FSW Joint

2012 ◽  
Vol 186 ◽  
pp. 331-334
Author(s):  
Mateusz Kopyściański ◽  
Stanislaw Dymek ◽  
Carter Hamilton
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Dislocation Density ◽  
Severe Plastic Deformation ◽  
Base Material ◽  
Friction Stir ◽  
Tem Characterization ◽  
Equiaxed Grains

This research characterizes the changes in microstructure that occur in friction stir welded extrusions of a novel 7042 aluminum alloy. Due to the presence of scandium the base material preserved the deformation microstructure with elongated grains and fairly high dislocation density. The temperature increase with simultaneous severe plastic deformation occurring during friction stir welding induced significant changes in the microstructure within the weld and its vicinity. The weld center (stir zone) was composed of fine equiaxed grains with residual dislocations and a modest density of small precipitates compared to the neighbouring thermomechanically and heat affected zones where the density of small precipitates was much higher.

Enhancement of Tribological Performance of 6061 Aluminum Alloy by Second Phase Hardening via Friction Stir Processing

2011 ◽  
Author(s):  
C. Lorenzo-Martin ◽  
O. Ajayi ◽  
G. Fenske
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Processing ◽  
Performance Enhancement ◽  
Base Material ◽  
Bearing Steel ◽  
Tribological Performance ◽  
Second Phase ◽  
Phase Hardening ◽  
Friction Stir ◽  
B4c Particle

The properties of metallic alloys can be substantial modified by the addition of a second phase particles. This is especially noticeable when hard particles are incorporated in a relatively soft matrix, often resulting in improved mechanical and tribological performance. This paper presents the results of our study on mechanical and tribological performance enhancement of 6061 Aluminum alloys by incorporation of B4C particle via Friction stir processing (FSP). Unidirectional ball on flat friction and wear tests were conducted with a base material, friction stir processed 6061-Al and 6061-Al doped with B4C particles via FSP against 52100 bearing steel balls under dry sliding conditions. The incorporation of particles not only reduced friction by 30% but also reduced wear by 2 orders of magnitude compared to unprocessed base and FSP material without particles incorporation. FSP alone without particles addition did not have a significant effect on the tribological behavior of the tested aluminum alloy.

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