Effect of Brazing Flux Pb on Microstructure and Mechanical Property of CMT Weld-Brazed Lap Joint of 5052 Aluminum Alloy to Galvanized Q235 Steel

2014 ◽  
Vol 789 ◽  
pp. 290-296 ◽  
Author(s):  
Hua Qing Lai ◽  
Sheng Lu

5052 aluminum alloy and galvanized Q235 steel sheets with thickness of 1mm were lap welded/brazed by cold metal transfer technology (CMT) with ER4043 as the filler wire and Pb foil as the brazing flux. Scanning electron microscope (SEM), microscope with super-depth, X-ray diffraction (XRD), electronic universal tensile testing machine and hardness tester were employed to study the microstructure and mechanical properties of the joint. The results indicate that Pb foil effectively improved the mechanical properties of the joint with tensile strength up to 160Mpa which is higher than that of the joint without the brazing flux of Pb foil. Intermetallic compound (IMC) layer in the brazing joint unequally distributed in the interface of aluminum alloy and galvanized steel. The thickness of IMC layer was about 1~3.5um. The main phases of the IMC layer were FeAl and AlFe6Si. Fine equiaxial crystals existed in the weld metal while columnar crystals existed in the fusion zone of aluminum alloy. The hardness of fusion zone was higher than base metal while the hardness of heat affected zone was lower than base metal. In most case, the lap joint was broken in the junction of base metal and fusion zone.

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 568
Author(s):  
Xinwei She ◽  
Xianquan Jiang ◽  
Bao Qi ◽  
Kang Chen

The effect of Er on microstructure and mechanical properties of the 5052 aluminum alloy with a big width-to-thickness ratio was investigated by a metallurgical microscope, scanning electron microscope and tensile testing machine. The results showed that the precipitates were slightly refined after Er addition and Al3Fe was transformed into Al6Fe and AlEr with/without a small amount of Fe or Si. The effect of Er on grain refinement was related to its content. When Er content was lower or higher than 0.4%, the grain would coarsen. Homogenization could refine the grain by controlling Er content and distribution in the Al matrix. Long time homogenization at high temperature would significantly reduce the strength of the 5052 aluminum alloy and 5052 aluminum alloys with low Er content, but help to improve the plasticity of those with high Er content. The ultimate tensile strength, yield strength and elongation of the as-cast 5052 aluminum alloy were 197 MPa, 117 MPa and 22.5% respectively. The strength was the highest, when Er content was 0.4 wt. % and the elongation was the best at 0.1 wt. % Er content.


2021 ◽  
Vol 1035 ◽  
pp. 114-118
Author(s):  
Chang Liang Shi ◽  
Yan Ping Niu ◽  
Yi Min Lin ◽  
Quan Hu ◽  
Xin Zhang

The effects of coarse-grained ring on the mechanical properties and cutting performance of 2011 aluminum alloy extruded bars were studied by metallographic microscope, scanning electron microscope, tensile testing machine and high-speed lathe. The results show that the microstructure of aluminum alloy extruded bar was composed of α-Al phase, Al7Cu2Fe phase, CuAl2 phase and SnBi eutectic phase. There was a coarse-grained ring in the aluminum alloy extruded bar. The coarse-grained ring reduced the mechanical properties and cutting performance of the aluminum alloy extruded bar. The aluminum alloy extruded bar with a diameter of 30 mm had a coarse-grained ring depth of 9 mm and lower mechanical properties, whose the tensile strength was 287.9 MPa, the elongation was 17%, the cutting performance was poor and the chips were long. The aluminum alloy extruded bar with a diameter of 40 mm had a coarse-grained ring depth of 1 mm, higher mechanical properties and better cutting performance, whose the tensile strength was 394.5 MPa, the elongation was 23.5%, the chips were fine and uniform.


2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940043
Author(s):  
Chuanping Ma ◽  
Guozheng Kang ◽  
Guoqing Gou ◽  
Hui Chen ◽  
Xiaoli Che

A7N01 aluminum alloy is widely used in rail transit industry due to its excellent comprehensive mechanical properties. However, due to its sensitivity to stress corrosion cracking (SCC), especially in hydrogen-containing moisture environment, the mechanical properties of hydrogen-charged A7N01 aluminum alloy friction stir welding (FSW) joints were tested through the tensile testing machine. The scanning electron microscopy (SEM) was used to study the tensile fracture morphology. The results indicate that the ductility and tensile strength loss of A7N01 Al alloy FSW joints are large in conditions of charging hydrogen. This is due to the embrittlement of the material caused by hydrogen infiltrating into the grain boundary of the aluminum alloy material.


2005 ◽  
Vol 475-479 ◽  
pp. 1001-1004
Author(s):  
Ninglin Zhou ◽  
Xiao Xian Xia ◽  
Li Li ◽  
Shao Hua Wei ◽  
Jian Shen

A novel exfoliated polyurethane (PU)/clay Interpenetrating Polymer Networks (IPNs) nanocomposite has been synthesized with polyurethane and organoclay. MTPAC is used as swelling agent to treat Na-montmorillonite for forming organoclay. The results indicate that there is very good compatibility between organoclay and PU. Nanoscale silicate dispersion was analyzed by XRD. The mechanical properties of the nanocomposites have been measured by tensile testing machine. The nanocomposites show obviously improved physical and mechanical properties when compared with the pure polymer. Additionally, PU /MTPAC- clay shows lower water absorption properties than pure PU do. In addition, the reinforcing and intercalating mechanism of silicate layers in polyurethane matrix are discussed.


2011 ◽  
Vol 365 ◽  
pp. 98-103
Author(s):  
De Quan Shi ◽  
Gui Li Gao ◽  
Zhi Wei Gao ◽  
Yan Liu Wang ◽  
Xu Dong Wang

The influence of Al-10RE addition, holding time and holding temperature on the microstructures and mechanical properties of ZL203 aluminum alloy has been studied respectively through using the optical microscope and the universal mechanical testing machine. The experimental results lead to the following conclusions. When Al-10RE addition is 1.0%-1.5%, the holding time is 15 minutes and the holding temperature is 730°C-750°C, the microstructure of Zl203 is perfect. With the increase of Al-10RE addition, the mechanical properties including tensile strength, elongation rate and hardness gradually increase. When the Al-10RE addition is 1.0%-1.5%, the mechanical properties reaches maximum. When the Al-10RE addition is above 1.5%, the mechanical properties decrease with the increase of Al-10RE addition.


Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2743
Author(s):  
Wen Dong ◽  
Rongrong Huang ◽  
Hongyun Zhao ◽  
Xiangtao Gong ◽  
Bo Chen ◽  
...  

Laser penetration welding of magnesium alloys and pure titanium TA2 with unequal thickness was performed. Mg base metal with different Al content (AZ31B, AZ61A, AZ91D) was used to investigate the influence of Al element in microstructure and mechanical properties of Mg/Ti dissimilar joints. The results revealed that the change of Mg base metal did not influence the weld appearance of the joints. Three kinds of joint all presented the best mechanical property when the laser power was 3500 W. With the increase content of Al elements in Mg base metal, a reaction layer was observed which was identified as Ti3Al. The highest enrichment of Al element was obtained and its fraction reached 19.31 at% at the AZ91/TA2 interface. The chemical potential gradient of Al from AZ91 to Ti alloy was higher than that from the other two base metals based on thermodynamic calculation. The maximum fracture load reached 3597 N when AZ61 was employed as the base metal and the fracture position was the Ti base metal. AZ31/TA2 joints failed at the weld seam without necking due to the rapid propagation of cracks at the Mg/Ti interface. The AZ91/TA2 joint failed inside the Mg fusion zone with necking at the middle area of the weld, which resulted from the precipitation of brittle phases such as Mg–Al, Ti–Al phases in the fusion zone of Mg alloys.


2017 ◽  
Vol 863 ◽  
pp. 323-327 ◽  
Author(s):  
Yustiasih Purwaningrum ◽  
Panji Lukman Tirta Kusuma ◽  
Dwi Darmawan

The aimed of this research is to investigate the effect of T-Joint’s root gap on physical and mechanical properties of weld metal. Low carbon steel were joined in T-joint types using MIG (Metal Inert Gas) with variation of root gap. The root gap used were 0 mm, 3 mm and 6 mm. The physical properties examined with chemical composition, microstructure and corrosion using optical microscope. The mechanical properties were measured with respect to the strength and hardness using Universal testing machine and Vickers Microhardness. The results show that the highest value found in welds with a gap of 3 mm with a value of 163.57 MPa. Hardness value is directly proportional to the tensile strength of the material. The highest value found in welds with root gap of 3 mm, followed by root gap of 6 mm, and 0 mm Hardness values in the welding area is higher than the parent metal and HAZ because the number of Si, Mn and Cu elements in the welding metals are bigger than base metal. Weld with all variation of root gap have a good corrosion resistance because the corrosion rate in welds with various root gap have a value below 0.02 mmpy. Microstructure of weld metals were Accicular ferrite, Widmanstatten ferrite, and grain boundary ferrite, while microstructure of base metal and HAZ were ferrite and perlite.


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