scholarly journals Corrosion Fatigue Fracture Characteristics of FSW 7075 Aluminum Alloy Joints

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4196
Author(s):  
Qingna Ma ◽  
Fei Shao ◽  
Linyue Bai ◽  
Qian Xu ◽  
Xingkun Xie ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Fatigue Fracture ◽  
Corrosion Fatigue ◽  
Weld Nugget ◽  
Fatigue Properties ◽  
Nugget Zone ◽  
Fracture Characteristics ◽  
Friction Stir ◽  
Secondary Cracks

The corrosion fatigue properties and fracture characteristics of friction stir welding joints of 7075 aluminum alloys were studied via corrosion fatigue tests, electrochemical measurements, and corrosion fatigue morphology and microstructure observations. The results show that the corrosion fatigue crack of the friction stir welding (FSW) joint of 7075 aluminum alloys originated in the junction zone between the thermomechanically affected zone and the weld nugget zone. The corrosion fatigue life of the joint decreased with increasing stress amplitude, with an S–N curve equation of lgN = 5.845 − 0.014S. Multiple crack sources were observed in the corrosion fatigue fracture. The main crack source originated from the corrosion pits at the interface between the thermomechanically affected zone and the weld nugget zone due to the influence of the coarse microstructure and the large potential difference between both zones. Corrosion morphologies of a rock candy block and an ant nest appeared in the crack propagation zone and the grain boundary of the weld nugget zone. In addition, fatigue speckles and intergranular fractures were observed, as well as brittle fracture characterized by cleavage steps and secondary cracks in the final fracture zone.

Multi-objective optimization of friction stir welding process parameters for joining of dissimilar AA5083/AA6063 aluminum alloys using hybrid approach

2016 ◽  
Vol 232 (4) ◽  
pp. 343-353 ◽  
Author(s):  
Saurabh Kumar Gupta ◽  
KN Pandey ◽  
Rajneesh Kumar
Keyword(s):  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Process Parameters ◽  
Hybrid Approach ◽  
Weld Nugget ◽  
Multi Objective Optimization ◽  
Nugget Zone ◽  
Friction Stir ◽  
Multi Objective ◽  
Dissimilar Aluminum Alloys

Joining of dissimilar aluminum alloys are widely used in automobile, aerospace and shipbuilding industries. The defect-free joining of aluminum alloys using conventional technique is a challenging task for a welding engineer. Friction stir welding has been established as one of the most promising processes for defects-free joining of aluminum alloys. In this study, a hybrid approach of grey relational analysis with principal component analysis, is applied for multi-objective optimization of process parameters for friction stir welding of dissimilar AA5083/AA6063 aluminum alloys. Three responses namely tensile strength, average hardness at weld nugget zone and average grain size at weld nugget zone, and four process parameters with three levels have been selected for the study. Taguchi method based L27 orthogonal array design matrix is used for experiments. The optimal set of process parameters using hybrid approach was found as 900 r/min of tool rotational speed, 60 mm/min of welding speed, 18 mm of shoulder diameter and 5 mm of pin diameter. Improved performance of each response was obtained from the confirmation tests at optimum level of parameters.

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.

Microstructure and Mechanical Properties of Friction Stir Welding Joint of Pure Copper

2011 ◽  
Vol 418-420 ◽  
pp. 1520-1523
Author(s):  
Yong Zhao ◽  
You Li Ye ◽  
Keng Yan ◽  
Li Long Zhou
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
High Speed ◽  
Bonding Temperature ◽  
Pure Copper ◽  
High Speed Steel ◽  
Weld Nugget ◽  
Nugget Zone ◽  
Friction Stir ◽  
Welding Joint

Microstructures and mechanical properties of pure copper weld joints are discussed under different parameters of friction stir welding. The results reveal that it is conducive to the formation of compact joint in friction stir welding by applying high speed steel tool with high anti-bonding temperature. The friction stir welding joint with compact and defect-free microstructure could be obtained when the tool rotation rate is 1250- 1650 r/min and the tool traverse speed is 20-50 mm/min. Intensively plastic deformation occurs in the soften materials of the weld nugget zone and numerous crystal particles are broken under the influence of tool stirring. The microstructure of weld nugget zone is composed of tiny isometric crystals, which is due to the dynamic recrystallization of broken crystal particles. The structure of thermo-mechanical affected zone on both sides is asymmetric. Obvious boundary of the thermo affected zone could be seen on the advancing side, and the plastic streamline is apparent.

Fatigue Properties and Fracture Characteristics of the Aluminum Alloys for High-Speed Train Carbody

2015 ◽  
Vol 1095 ◽  
pp. 437-441
Author(s):  
Fan Qiu ◽  
Qiang Li
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloys ◽  
Fatigue Fracture ◽  
High Speed ◽  
Fatigue Cracks ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Fracture Characteristics ◽  
Initiation Zone ◽  
Propagation Zone

The fatigue tests on two types of domestic aluminum alloys were conducted and the P-S-N curves of both aluminum alloys were obtained. The microscopic characteristics at the fatigue fracture surface were observed with scanning electron microscopy. The results show that the tensile strength of A7 is 376MPa, while the tensile strength of A6 is 311MPa. The fatigue strength of A7 is 75MPa at 107 circles, and it is just a little higher than that of A6, which is 71.57MPa. The fatigue cracks initiated from or near the surface of the specimen. The fatigue fracture can be divided into three parts, namely, the initiation zone, the propagation zone and the sudden fracture zone. Typical characteristics could be observed on fracture surface.A6 has better plasticity than A7.

scholarly journals Characteristics of Alsi9mg/2017A Aluminum Alloys Friction Stir Welded with Offset Welding Line and Root-Side Heating/ Charakterystyka Stopów Aluminium Alsi9mg/2017A Zgrzewanych Metodą Friction Stir Welding Z Przesunięcem Linii Zgrzewania I Dodatkowym Źródłem Ciepła Od Strony Grani

2014 ◽  
Vol 59 (4) ◽  
pp. 1293-1299 ◽  
Author(s):  
K. Mroczka
Keyword(s):  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Cast Alloy ◽  
Natural Aging ◽  
Weld Nugget ◽  
Hardness Distribution ◽  
Additional Heat ◽  
Friction Stir ◽  
Alloy Hardness ◽  
Welding Line

Abstract Welding of materials differing significantly in terms of chemical composition and microstructure is one of the main advantages of the Friction Stir Welding method. This paper presents the results of welding of a cast AlSi9Mg (hypoeutectic silumin) and 2017A aluminum alloys. The welding was performed with a high linear velocity (over 1 m/min). The modification of the process consisted in offsetting the welding line toward the advancing side, and in on application of an additional heat source from the root side. The study of the macrostructure (with high resolution of the image) revealed the presence of defects in the weld, despite greater plasticity of the material results from raising the temperature. The analysis (by SEM, SEM-EDS) of constituent stable phases within the cast alloy, showed their considerable fragmentation, however to a various degree. The material above the weld nugget was not mixed and contained micro-defects that did not result from the welding. The hardness distribution within the weld nugget, reveals slight strengthening of the both cast and wrought alloys. A metastable state of the 2017A alloy was also documented, however, the alloy hardness increased within the weld nugget due to the natural aging. On the other hand, the hardness of the heat-affected zone in this alloy does not increase also due to the natural aging.

The Effects of Heat Treatment and Cold Working on the Microstructure of Aluminum Alloys Welded by Friction Stir Welding (FSW) Technique

2011 ◽  
Vol 409 ◽  
pp. 287-292
Author(s):  
M. Mohammadtaheri ◽  
M. Haddad-Sabzevar ◽  
Mohammad Mazinani
Keyword(s):  
Grain Size ◽  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Cold Work ◽  
Base Material ◽  
Work Conditions ◽  
Weld Nugget ◽  
Hardness Profile ◽  
Friction Stir ◽  
Average Grain Size

The application of hot deformation during Friction Stir Welding (FSW) gives rise to produce a weld nugget consisting usually of dynamically recrystallized grains whose size is substantially lower than that of the base material. In the present study, several specimens with different conditions were first prepared using 2024 and 5083 aluminum alloys, which were then welded with FSW method. The microstructures of weld nugget in both series of specimens were examined using optical and scanning electron microscopes. The specimen of 2024 with anneal (O) and artificial aging (T6) conditions, and type 5083 with anneal (O), 30% and 50% cold work conditions were friction stir welded. Grain size distribution, hardness and temperature profiles in the welded zones were determined in order to obtain the relationship between the grain structure and the hardness profile in these regions. In each alloy, the average grain size in the weld nuggets was identical. The hardness of nugget zones in each alloy was the same due to their similar microstructures. According to the results obtained in this investigation, the initial microstructure showed no considerable effect on final microstructure and hardness of the weld nuggets, which this effect may be attributed to continuous dynamic recrystallization phenomenon.

Comparison of Friction Stir and Tungsten Inert Gas Weldments of AA6061-T6

2013 ◽  
Vol 858 ◽  
pp. 19-23
Author(s):  
Mohd Rafiza Shaari ◽  
Zuhailawati Hussain ◽  
Indra Putra Almanar ◽  
Nguyen Van Thuong
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Fusion Zone ◽  
Aluminium Alloys ◽  
Inert Gas ◽  
Nugget Zone ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
And Tungsten

In this research, 6061-T6 aluminum alloys were welded using friction stir welding and tungsten inert as techniques in order to investigate the microstructure and mechanical properties. FSW of aluminium alloys has showed better mechanical properties compared to the conventional welding, tungsten inert gas (TIG). FSW weldment did not show any pores at the nugget zone compared to fusion zone in TIG weldment which produced a lot of pores.

Mechanical property and characterization of 7A04-T6 aluminum alloys bonded by friction stir welding

2020 ◽  
Vol 52 ◽  
pp. 263-269 ◽  
Author(s):  
Jianing Li ◽  
Molin Su ◽  
Wenjun Qi ◽  
Chen Wang ◽  
Peng Zhao ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Friction Stir
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