Improved Recrystallization Resistance and Welding Properties of Cold-Rolled Al-Mg Alloy Sheets by Microalloying with Sc and Zr

2021 ◽  
Vol 1035 ◽  
pp. 17-24
Author(s):  
Hao Wu ◽  
Zhi Kai Zheng ◽  
Si Meng Ren ◽  
Shu Lei Li ◽  
Hu Wang ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Welded Joints ◽  
Alloy Sheet ◽  
Mg Alloy ◽  
Softening Effect ◽  
Welding Temperature ◽  
Friction Stir ◽  
Alloy Increase ◽  
Welding Properties ◽  
Zr Alloy

The effects of Sc and Zr element on the recrystallization behavior and microstructure evolution of Al-Mg alloy had been researched in this paper, and meanwhile, the microstructure and mechanical properties of the friction stir welding joints were also analyzed. The results show that the recrystallization and grain growth behavior of Al-Mg-Sc-Zr alloy can be inhibited effectively by microalloying with Sc and Zr. Compared with Al-Mg and Al-Mg-Zr alloys, the recrystallization start temperature and finish temperature of Al-Mg-Sc-Zr alloy increase significantly, and the strength of alloy sheet which subjected to stabilizing annealing is increased by more than 50MPa. Moreover, the recrystallization softening effect of the welded joints microstructure, which caused by the welding temperature field and welding heat input, can be weaken by microalloying with Sc and Zr, the width of recrystallization zone is reduced, the microstructure and properties of the welded joints are improved. The friction stir welding coefficients of Al-Mg-Sc-Zr alloy increases to 86.9%.

scholarly journals The Effects of SiC Particle Addition as Reinforcement in the weld Zone during Friction Stir Welding of Magnesium Alloy AZ31B

2016 ◽  
Vol 3 (3) ◽  
Author(s):  
Md. Aleem Pasha ◽  
Dr. P. Ravinder Reddy ◽  
Dr. P. Laxminarayana ◽  
Dr. Ishtiaq Ahmad Khan
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Welded Joints ◽  
Weld Zone ◽  
Mg Alloy ◽  
Friction Stir ◽  
Sic Particles ◽  
Magnesium Alloy Az31b ◽  
Sic Particulates

<div><p><em>Welding of magnesium alloys influence a great effect on magnesium application expansion, especially in marine and aerospace where large-size, complex components are required. Due to specific physical properties of magnesium, its welding requires great control. In general, the solid-state nature of friction stir welding (FSW) process has been found to produce a low concentration of defects. Mechanical properties of  friction stir welded joints are decreases than base material, so to enhance the mechanical properties of welded portion, In the present research additional SiC particulates were incorporated in the weld interface of friction stir welding of Magnesium alloy AZ31B. Silicon Carbide has been added as reinforcement by creating separate geometry, at the edges where the welding is interface with 4 different volume proportions such as 10%, 15%, 25% and 30%. Tool Steel of H13 grade has been used as friction stir welding tool. Rotational Speed of 1400 RPM and Transverse Speed of 25 mm/min were selected. Joined Mg Alloy AZ31B alloy plates were evaluated for their mechanical properties under two different conditions, i.e in the un-reinforced welded condition and reinforced welded conditions. The results of the study revealed that the mechanical properties of the SiC particulates added Mg alloy AZ31B welded joints are superior in all four proportions of SiC, compared to un-reinforced Mg alloy AZ31B welded joints. Microstructural examination of the welded joints was conducted using Optical microscope and revealed that distribution of SiC particles producing increased weld strength. The comparison of the microstructures and mechanical properties of unreinforced Friction stir welded AZ31 with those of SiC reinforced FS-welded joints showed that the addition of SiC particles decreased the grain size and increased the strength.</em></p></div>

scholarly journals Microstructural Evolutions of 2N Grade Pure Al and 4N Grade High-Purity Al during Friction Stir Welding

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3606
Author(s):  
Tomoya Nagira ◽  
Xiaochao Liu ◽  
Kohasaku Ushioda ◽  
Hidetoshi Fujii
Keyword(s):  
Friction Stir Welding ◽  
Dynamic Recrystallization ◽  
Grain Refinement ◽  
High Purity ◽  
Cube Texture ◽  
Grain Structure ◽  
Welding Temperature ◽  
Friction Stir ◽  
Continuous Dynamic Recrystallization ◽  
Dislocation Annihilation

The grain refinement mechanisms along the material flow path in pure and high-purity Al were examined, using the marker insert and tool stop action methods, during the rapid cooling friction stir welding using liquid CO2. In pure Al subjected to a low welding temperature of 0.56Tm (Tm: melting point), the resultant microstructure consisted of a mixture of equiaxed and elongated grains, including the subgrains. Discontinuous dynamic recrystallization (DDRX), continuous dynamic recrystallization (CDRX), and geometric dynamic recrystallization are the potential mechanisms of grain refinement. Increasing the welding temperature and Al purity encouraged dynamic recovery, including dislocation annihilation and rearrangement into subgrains, leading to the acceleration of CDRX and inhibition of DDRX. Both C- and B/-type shear textures were developed in microstructures consisting of equiaxed and elongated grains. In addition, DDRX via high-angle boundary bulging resulted in the development of the 45° rotated cube texture. The B/ shear texture was strengthened for the fine microstructure, where equiaxed recrystallized grains were fully developed through CDRX. In these cases, the texture is closely related to grain structure development.

Friction Stir Welding of Dissimilar Formed Mg Alloys (AZ31/AZ91)

2005 ◽  
Vol 486-487 ◽  
pp. 249-252 ◽  
Author(s):  
Chang Yong Lee ◽  
Won Bae Lee ◽  
Yun Mo Yeon ◽  
Seung Boo Jung
Keyword(s):  
Friction Stir Welding ◽  
Dynamic Recrystallization ◽  
Tensile Test ◽  
Intermetallic Compounds ◽  
Grain Growth ◽  
Weld Zone ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Friction Stir ◽  
Az31 Mg Alloy

Friction stir welding of dissimilar formed Mg alloys(AZ31/AZ91) was successfully carried out at the limited welding conditions. In a sound joint, SZ was mainly consisted of AZ31 Mg alloy which was located the retreating side. Dynamic recrystallization and grain growth occurred and β intermetallic compounds of AZ 91 Mg alloy was not observed in SZ. BM had a higher hardness than that of the weld zone. The fracture location was not weld zone but BM of the AZ91 Mg alloy in tensile test.

Process Relationship in High-Stress Friction Coupled with Complex Shaped Counterbody and Friction Stir Welding Al-Mg-Sc-Zr Alloy

2022 ◽  
Vol 1049 ◽  
pp. 39-44
Author(s):  
Andrey Chumaevskii ◽  
Denis Gurianov ◽  
Anastasiya Gusarova ◽  
Anna Zykova ◽  
Aleksandr Panfilov ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Complex Shape ◽  
High Stress ◽  
Large Crystal ◽  
Friction Zone ◽  
Friction Stir ◽  
Model Research ◽  
Alloy Material ◽  
Distinguishing Features ◽  
Zr Alloy

Model research tests of plastic deformation, fragmentation and flow of aluminum alloy material of Al-Mg-Sc-Zr system under high loaded friction in pair with a steel counterbody of a complex shape and comparison of the obtained result with the structure formed by friction stir welding have been carried out. The conducted studies show that the structure formed by extrusion of the material from the friction zone and its compaction in the channel of the counterbody is, in general, close in structure to the structure formed by friction stir welding of similar material. The distinguishing features of the structure formed in the model experiments on friction include the introduction into the stirring zone of material with deformed large-crystal structure, increased grain size of the stirring zone, the presence of defects and differences in the geometry of the stirring zone.

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.

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