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.

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%.

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.

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.

OS1520 Effects of Roller Burnishing and Friction Stir Processing on Fatigue Properties in a Cast Aluminum Alloy

2013 ◽  
Vol 2013 (0) ◽  
pp. _OS1520-1_-_OS1520-3_
Author(s):  
Hiroaki MASUDA ◽  
Yuki NAKAMURA ◽  
Masaki NAKAJIMA ◽  
Toshifumi KAKIUCHI ◽  
Yoshihiko UEMATSU
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Processing ◽  
Fatigue Properties ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Friction Stir ◽  
Roller Burnishing

Microstructure and Cryogenic Mechanical Properties of AA5083 Joints Prepared by Friction Stir Welding

2014 ◽  
Vol 788 ◽  
pp. 243-248 ◽  
Author(s):  
Bao Kang Gu ◽  
Da Tong Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Tensile Testing ◽  
Base Material ◽  
Tensile Behavior ◽  
Planar Slip ◽  
Friction Stir ◽  
5083 Aluminum Alloy ◽  
Cryogenic Mechanical Properties

In this study, 5083 aluminum alloy plates with a thickness of 3mm are friction stir welded and the microstructure and mechanical properties of the joints were characterized. In particular, tensile behavior of the joints is examined at 77K. It is found that defect-free joints can be obtained under a tool rotational rate of 800rpm and a welding speed of 60mm/min. The friction stirring welds exhibit finer microstructure and higher hardness than that of the base material due to the grain refinement. The ultimate tensile strength (UTS) and elongation of the joints measured at 298K are 316MPa and 21.3%, which are nearly equal to those of the base material. With the tensile test temperature decreasing to 77K, UTS and elongation of both the base material and joints increase. Comparing with tensile testing at 298K, dimples on the fracture surface of the samples tested at 77K are more uniform in distribution. The improvement of the mechanical properties of specimens at low temperature is related to the inactivation of planar slip and the strengthening of strain hardening.

Influence of Friction Stir Processing Parameters on Anisotropic Behavior Property of 5086-O Aluminum Alloy

2011 ◽  
Vol 702-703 ◽  
pp. 348-351
Author(s):  
Shivanna Pradeep ◽  
Sumit Kumar Sharma ◽  
Vivek Pancholi
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Processing ◽  
Rotation Speed ◽  
Base Material ◽  
Processing Parameters ◽  
Mechanical Anisotropy ◽  
Al Alloy ◽  
Anisotropic Behavior ◽  
Planar Anisotropy ◽  
Friction Stir

In the present work, 5086 Al alloy is subjected to single and multi pass friction stir processing (FSP) to modify microstructure and mechanical anisotropy. The processing is carried out at constant rotation speed of 1025 rpm and different traverse speeds of 30 mm/min and 50 mm/min with and without cooling. Mechanical anisotropy is evaluated in terms of normal and planar anisotropy by performing tensile test in 0, 45 and 90o direction to processing direction. Material processed using multi pass FSP at 30 mm/min is showing lower planar anisotropy as compared to base material. The mechanical anisotropy property is correlated with the development of micro texture.

Optimization of transversal flow stress and strain and weld seam microstructure analysis in butt-HDPE friction stir welded plates

2020 ◽  
Vol 21 (5) ◽  
pp. 501
Author(s):  
Khaled Hamrouni ◽  
Mohamed-Ali Rezgui ◽  
Ali Trabelsi ◽  
Zoltan Kiss ◽  
Rachid Nasri
Keyword(s):  
Flow Stress ◽  
Failure Modes ◽  
Rotation Speed ◽  
Base Material ◽  
Microscopic Analysis ◽  
Structural Defects ◽  
Stress And Strain ◽  
Friction Stir ◽  
Welded Seam ◽  
Transversal Flow

The paper aims to optimize the characteristic performances of friction stir welding of high-density polyethylene in order to predict failure modes in weld nugget and interfacial zones. Three replicates of a face central composite design are employed to estimate the effects of parameters process, on the transversal flow stress and strain of the seam and to understand root causes, which may lead to structural defects such as the onset of cracks and the seam-base metal rupture. The study findings disclose that maximum responses are obtained when the tool rotation speed is set middle and both the feed rate and the plunged surface are set high. The transversal flow stress of the welded seam is found highly sensitive to the plunged surfaces and at a lesser degree to the rotation speed, whereas, the transversal flow strain of the welded seam is mostly sensitive to the rotation speed and at a lesser degree to the plunged surfaces. For the microscopic analysis, it is shown that at low rotation speed, there exist four structural layers in the transition zone between the seam and the base material giving rise to the formation of a continuous line of cracks that can initiate structure failure.

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