scholarly journals Effects of Rotation Speed on Microstructure and Mechanical Properties in Ti/Cu Dissimilar Friction Stir Welding

2021 ◽  
Vol 59 (12) ◽  
pp. 886-892
Author(s):  
Yong-Jae Lee ◽  
Won-Ki Jung ◽  
Se-Eun Shin ◽  
Dong-Geun Lee

The dissimilar welding of titanium and copper by fusion welding is very difficult because the melting points of the materials are very highly different and strong brittle intermetallic compounds (IMCs) can be easily produced in welded zone and heat-affected zone, etc. Friction stir welding was employed as a type of solid-state welding for Ti/Cu dissimilar welding to obtain a sound welded zone and reduce the total process cost. This study investigated how the metal flow of the welded zone changes according to the variation in the rotational speed of the tool, from 450 rpm to 600 rpm. When the rotational speed was too high, the plastic flow of the softened material increased and intermetallic compounds such as TiCu, Ti2Cu3, and Ti2Cu, were generated in the Cu region of the welded zone. The microstructural evolution of AS (Advancing Side) and RS (Retreating Side) were investigated and the soundness of the welded zone and its mechanical properties were evaluated through the microstructural evolution. A high hardness value of 200 Hv or more was exhibited in some points, due to the formation of intermetallic compounds in the RS (Cu) region. Ti/Cu dissimilar friction stir welding at a welding speed of 50 mm/min and an appropriate rotation speed of 500 rpm showed a good welded zone and mechanical properties.

2020 ◽  
Vol 13 (2) ◽  
pp. 49
Author(s):  
Muhammad Arsyad Suyuti ◽  
Apollo . ◽  
Muhammad Iswar ◽  
Rusdi Nur

The joint for two different materials (AA5052 and AA6061) can be done by the Dissimilar Friction Stir Welding (DFSW) process. Therefore, this study was conducted to analyze the mechanical properties of dissimilar welding joints. In this study the DFSW process uses a tool with a shoulder Ø 17.8 mm and a cylindrical pin Ø 5 mm. FSW blocking is done on conventional milling machines with 1300 rpm, 1950 rpm and 2850 rpm tool rotation variations, while the welding speed variations are 43 mm / min, 130 mm / min and 240 mm / min. The results of mechanical properties testing showed the highest hardness value obtained was 55.3 HBN at 1300 rpm with 240 mm / min feeding, the highest tensile strength occurred for 1300 rpm and 240 mm / min feeding at 123.51 MPa. The fracture of the tensile test results generally occurs in the HAZ area and the AA5052 base metal Nugget. Investigation results show that the DFSW connection of aluminum alloy material AA 6061 and AA 5052 adapt is well connected, but in terms of general strength the tensile strength of the joint (HAZ and Nugget) is smaller than the tensile strength of the base metal. This DFSW connection adaptation is applied to connections that do not accept load or tensile strength due to the load received by the connection not to exceed the maximum tensile strength of base metal AA 5052  


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1938
Author(s):  
Haifeng Yang ◽  
Hongyun Zhao ◽  
Xinxin Xu ◽  
Li Zhou ◽  
Huihui Zhao ◽  
...  

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.


Author(s):  
Adel Sedaghati ◽  
Hamed Bouzary

In this paper, the effect of water cooling on mechanical properties and microstructure of AA5086 aluminum joints during friction stir welding is investigated. For doing so, the mechanical and microstructural behavior of samples welded both in air and in water was analyzed. Tests were performed involving both butt and lap welds and the results were compared. The effect of rotational speed at constant feed rate of 50 mm/min and changing rotational speed ranging from 250 to 1250 r/min was investigated. The results showed a significant change in the tensile behavior of the butt-welded specimens due to water cooling. In addition, welding was performed at constant spindle speed of 800 r/min and various traverse speeds (25 mm/min to 80 mm/min) to determine the effect of feed rate. The strength increases at first, but then decreases dramatically along with the feed rate which is due to the occurrence of a groove defect. Results showed some generally positive impacts of water cooling which are discussed in terms of tensile results, hardness distributions and microstructure analysis.


Sign in / Sign up

Export Citation Format

Share Document