Study on the Microstructure and Properties of Zl114a Friction Stir Welded Joint with Forced Cooling

2011 ◽  
Vol 189-193 ◽  
pp. 3335-3338
Author(s):  
Ge Ping Liu ◽  
Yu Hua Chen ◽  
Hong Yan Wu ◽  
Li Ming Ke
Keyword(s):  
Welded Joint ◽  
Silicon Particle ◽  
Welding Process ◽  
Weld Nugget ◽  
Air Cooling ◽  
Micro Hardness ◽  
Nugget Zone ◽  
Friction Stir ◽  
Microstructure And Properties ◽  
Forced Cooling

ZL114A was joined by friction stir welding and liquid nitrogen was used to cool the welded joint during the welding process. The Influence of forced cooling on the microstructure and properties of welded jointed was studied. The results show that, when forced cooling is used, the amount of silicon particles in weld nugget zone is larger and the size is more homogeneous, the size of silicon particle in heat-mechanical affected zone is more fine , the grain size of heat affected zone is half of air cooling welded joint and the amount of Al-Si eutectic is smaller than air cooling welded joint. The micro hardness increases after forced cooling is used, the hardness of weld nugget zone is 20Hv higher than air cooling welded joint. The strength of forced cooling welded joint increases 13.6% than air cooling welded joint.

scholarly journals Incorporating oxygen-free copper to improve the microstructure and mechanical properties of friction-stir-welded joints for aluminum alloys

2018 ◽  
Vol 25 (6) ◽  
pp. 1219-1228
Author(s):  
Her-Yueh Huang ◽  
Chung-Wei Yang ◽  
Wen-Yao Deng
Keyword(s):  
Mechanical Properties ◽  
Rotation Speed ◽  
Welding Process ◽  
Weld Nugget ◽  
Nugget Zone ◽  
Friction Stir ◽  
Copper Particles ◽  
Dissimilar Metal ◽  
Tool Rotation ◽  
Traveling Speed

AbstractThe main objective of the present work was to establish a friction-stir-welding process to weld dissimilar metal joints on AA6082 and AA6066 aluminum alloy plates. Joints were made while varying tool rotation speed at a constant traveling speed and at the same time adding oxygen-free copper reinforcement inside the weld nugget for the purpose of analyzing the microstructural evolution and mechanical properties of the joint. Results showed that the morphology of the microstructure in the weld nugget changed significantly with rotation speed. Optical microscopy, scanning electron microscopy, and energy dispersive spectroscopy analyses revealed that oxygen-free copper particles could be uniformly dispersed into the weld nugget because of higher rotation speeds. Because of the presence of reinforcement particles homogenously distributed inside the nugget zone, the mechanical properties, such as ultimate tensile strength and hardness of weld joint, were greatly improved.

Microstructures and Properties of FSW Joints of AZ31B Mg Alloy

2011 ◽  
Vol 291-294 ◽  
pp. 855-859 ◽  
Author(s):  
Si Rong Yu ◽  
Xian Jun Chen
Keyword(s):  
Mechanical Properties ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Base Material ◽  
Alloy Sheet ◽  
Weld Nugget ◽  
Mg Alloy ◽  
Material Strength ◽  
Nugget Zone ◽  
Friction Stir

The extruded AZ31B Mg alloy sheet was welded with friction stir welding. The microstructures and mechanical properties of the welded joint were investigated. The results show that the grains in the weld nugget zone were small, uniform and equiaxed. The grains in thermo-mechanical affected zone were stretched and relatively small, but were not as small and uniform as those in the weld nugget zone. The grains in the heat-affected zone were relatively coarse. The fracture of the welded joint occurred mainly in the heat affected zone. The tensile strength of the welded joints was up to 257.4 MPa and was 87.9% of the base material strength. The microhardness in the weld nugget zone was higher. The microhardness in the thermo-mechanical affected zone and heat affected zone were lower than that in the weld nugget zone. The microhardness in the weld nugget zone increased from the upper surface to the bottom.

Joining of Q235 Low-Carbon Steel Plates by Friction Stir Welding With AA2A12 Strip As an Auxiliary Solder

2019 ◽  
Author(s):  
Peng Zhang ◽  
Shengdun Zhao ◽  
Peng Dong ◽  
Yongfei Wang ◽  
Chao Chen ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Melting Point ◽  
Welded Joint ◽  
Low Carbon Steel ◽  
Welding Process ◽  
Steel Plates ◽  
Low Carbon ◽  
Micro Hardness ◽  
High Melting Point ◽  
Friction Stir

Abstract This article proposed a novel friction stir welding process to weld high melting point alloy plates with low melting point alloy strip as auxiliary solder to reduce the wear of the friction stir welding tool and extend its service life, and feasibility of this process was evaluated. An AA2A12 strip was clamped to the gap between two Q235 low-carbon steel plates as an auxiliary solder before welding, then a joint with excellent surface quality and smooth weld edge transition was obtained by friction stir welding process in which the tool was made of low-cost material tungsten-carbide. Macrostructure, microstructure and fracture surface of the joints were investigated by optical microscope and scanning electron microscope. The tensile tests were conducted to evaluate the mechanical properties of the joint at rotational speed of 800 r/min, traverse speed of 50 mm/min, with plunge depth and probe offset of 0.1 mm. The tensile strength of the joint was 108.9 MPa at room temperature what proved the feasibility of the novel way we proposed. The micro-hardness value of the cross section of the welded joint is M-shaped from the AS to the RS, and gradually decrease from the top plane to the bottom plane. There is a certain relationship between the welding process parameters and the macroscopic morphology, micro-hardness and mechanical properties of the welded joint. Hence, the method we proposed has high innovation, and economy, high value of scientific research and industrial application, and provides a new idea about friction stir welding of high melting point alloys.

Effects of bottom plate in friction stir welding of AA6061-T6

2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Axial Load ◽  
Weld Zone ◽  
Welding Process ◽  
Bottom Plate ◽  
Welding Parameters ◽  
Nugget Zone ◽  
Friction Stir ◽  
Weld Joints ◽  
Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

scholarly journals Effect of Stirring Pin Rotation Speed on Microstructure and Mechanical Properties of 2A14-T4 Alloy T-Joints Produced by Stationary Shoulder Friction Stir Welding

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1938
Author(s):  
Haifeng Yang ◽  
Hongyun Zhao ◽  
Xinxin Xu ◽  
Li Zhou ◽  
Huihui Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Rotation Speed ◽  
Weld Nugget ◽  
Al Alloy ◽  
Nugget Zone ◽  
T Joints ◽  
Friction Stir ◽  
Stationary Shoulder ◽  
Microstructure And Mechanical Properties

In this study, 2A14-T4 Al-alloy T-joints were prepared via stationary shoulder friction stir welding (SSFSW) technology where the stirring pin’s rotation speed was set as different values. In combination with the numerical simulation results, the macro-forming, microstructure, and mechanical properties of the joints under different welding conditions were analyzed. The results show that the thermal cycle curves in the SSFSW process are featured by a steep climb and slow decreasing variation trends. As the stirring pin’s rotation speed increased, the grooves on the weld surface became more obvious. The base and rib plates exhibit W- or N-shaped hardness distribution patterns. The hardness of the weld nugget zone (WNZ) was high but was lower than that of the base material. The second weld’s annealing effect contributed to the precipitation and coarsening of the precipitated phase in the first weld nugget zone (WNZ1). The hardness of the heat affect zone (HAZ) in the vicinity of the thermo-mechanically affected zone (TMAZ) dropped to the minimum. As the stirring pin's rotation speed increased, the tensile strengths of the base and rib plates first increased and then dropped. The base and rib plates exhibited ductile and brittle/ductile fracture patterns, respectively.

Influence of Friction Stir Welding Process on the Weld Formation and Tensile Strength of Titanium and Aluminum Dissimilar Alloys Welded Joint

2011 ◽  
Vol 189-193 ◽  
pp. 3266-3269 ◽  
Author(s):  
Yu Hua Chen ◽  
Peng Wei ◽  
Quan Ni ◽  
Li Ming Ke
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Cross Section ◽  
Welded Joint ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Influence Of Process Parameters ◽  
Friction Stir ◽  
Dissimilar Alloys ◽  
Titanium Aluminum

Titanium alloy TC1 and Aluminum alloy LF6 were jointed by friction stir welding (FSW), and the influence of process parameters on formation of weld surface, cross-section morphology and tensile strength were studied. The results show that, Titanium and Aluminum dissimilar alloy is difficult to be joined by FSW, and some defects such as cracks and grooves are easy to occur. When the rotational speed of stir head(n) is 750r/min and 950r/min, the welding speed(v) is 118mm/min or 150mm/min, a good formation of weld surface can be obtained, but the bonding of titanium/aluminum interface in the cross-section of weld joint is bad when n is 750r/min which results in a low strength joint. When n is 950r/min and v is 118mm/min，the strength of the FSW joint of Titanium/Aluminum dissimilar materials is 131MPa which is the highest．

Features of structure formation processes in AA2024 alloy joints formed by the friction stir welding with bobbin tool

2021 ◽  
Vol 23 (2) ◽  
pp. 98-115
Author(s):  
Alexey Ivanov ◽  
◽  
Valery Rubtsov ◽  
Andrey Chumaevskii ◽  
Kseniya Osipovich ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Structure Formation ◽  
Welded Joints ◽  
Heat Input ◽  
Welded Joint ◽  
Welding Process ◽  
Tool Material ◽  
Travel Speed ◽  
Material System ◽  
Friction Stir

Introduction. One of friction stir welding types is the bobbin friction stir welding (BFSW) process, which allows to obtain welded joints in various configurations without using a substrate and axial embedding force, as well as to reduce heat loss and temperature gradient across the welded material thickness. This makes the BFSW process effective for welding aluminum alloys, which properties are determined by their structural-phase state. According to research data, the temperature and strain rate of the welded material have some value intervals in which strong defect-free joints are formed. At the same time, much less attention has been paid to the mechanisms of structure formation in the BFSW process. Therefore, to solve the problem of obtaining defect-free and strong welded joints by BFSW, an extended understanding of the basic mechanisms of structure formation in the welding process is required. The aim of this work is to research the mechanisms of structure formation in welded joint of AA2024 alloy obtained by bobbin tool friction stir welding with variation of the welding speed. Results and discussion. Weld formation conditions during BFSW process are determined by heat input into a welded material, its fragmentation and plastic flow around the welding tool, which depend on the ratio of tool rotation speed and tool travel speed. Mechanisms of joint formation are based on a combination of equally important processes of adhesive interaction in “tool-material” system and extrusion of metal into the region behind the welding tool. Combined with heat dissipation conditions and the configuration of the “tool-material” system, this leads to material extrusion from a welded joint and its decompaction. This results in formation of extended defects. Increasing in tool travel speed reduce the specific heat input, but in case of extended joints welding an amount of heat released in joint increases because of specific heat removal conditions. As a result, the conditions of adhesion interaction and extrusion processes change, which leads either to the growth of existing defects or to the formation of new ones. Taking into account the complexity of mechanisms of structure formation in joint obtained by BFSW, an obtaining of defect-free joints implies a necessary usage of various nondestructive testing methods in combination with an adaptive control of technological parameters directly in course of a welding process.

Enhancements on dissimilar friction stir welding between AZ31 and SPHC mild steel with Al-Mg as powder additives

2021 ◽  
pp. 1-22
Author(s):  
Mohd Ridha Muhamad ◽  
Sufian Raja ◽  
Mohd Fadzil Jamaludin ◽  
Farazila Yusof ◽  
Yoshiaki Morisada ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Mild Steel ◽  
Welding Speed ◽  
Welded Joint ◽  
Microstructural Analysis ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Friction Stir ◽  
Welding Interface

Abstract Dissimilar materials joining between AZ31 magnesium alloy and SPHC mild steel with Al-Mg powder additives were successfully produced by friction stir welding process. Al-Mg powder additives were set in a gap between AZ31 and SPHC specimen's butt prior to welding. The experiments were performed for different weight percentages of Al-Mg powder additives at welding speeds of 25 mm/min, 50 mm/min and 100 mm/min with a constant tool rotational speed of 500 rpm. The effect of powder additives and welding speed on tensile strength, microhardness, characterization across welding interface and fracture morphology were investigated. Tensile test results showed significant enhancement of tensile strength of 150 MPa for 10% Al and Mg (balance) powder additives welded joint as compared to the tensile strength of 125 MPa obtained for welded joint without powder additives. The loss of aluminium in the alloy is compensated by Al-Mg powder addition during welding under a suitable heat input condition identified by varying welding speeds. Microstructural analysis revealed that the Al-Mg powder was well mixed and dispersed at the interface of the joint at a welding speed of 50 mm/min. Intermetallic compound detected in the welding interface contributed to the welding strength.

scholarly journals Refined Microstructure and Enhanced Hardness in Friction Stir-Welded AZ31 Magnesium Alloy Induced by Heat Pipe with Different Cooling Liquid

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1227 ◽  
Author(s):  
Yu-Meng Zhang ◽  
Liang-Yu Chen ◽  
Sheng Lu ◽  
Cuihua Zhao ◽  
Yi-Hao Wang
Keyword(s):  
Magnesium Alloy ◽  
Heat Pipe ◽  
Middle Part ◽  
Weld Nugget ◽  
Az31 Magnesium Alloy ◽  
Temperature Fields ◽  
Nugget Zone ◽  
Friction Stir ◽  
Cooling Liquid ◽  
Ice Water

The temperature field in welded plates has a significant influence on the microstructure and thereby their properties during friction stir welding (FSW). In this work, a self-designed heat pipe with different cooling liquid was applied in the FSW process for AZ31 magnesium alloy. The temperature fields, microstructures and properties of the welded joints were investigated. The peak temperatures and the durations of high temperature at both the advancing side and the retreating side decrease during the FSW process after applying the heat pipe and adding the ambient temperature water in the condensing tank. The top part of the weld nugget zone of the joint shows a significant decrease as well as its middle part due to the cooling effect of the heat pipe. The microstructure of the weld nugget zone is refined, associated with the increase in the hardness after applying the heat pipe. When the cooling liquid turns into ice water, grains in the weld nugget zone become significantly smaller and have a more homogeneous size. The mean value of hardness increases and the corresponding deviation is declined. Therefore, these results indicate that the application of the heat pipe and the employment of ice water as the cooling liquid can further refine the microstructure and enhance the strength of the material.

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