The Zn-added ultrasonic assisted friction stir lap welding(UaFSLW) was carried out to improve the quality of dissimilar Al/Mg alloys joint. The effects of ultrasonic power on the joint quality were also investigated.T...The Zn-added ultrasonic assisted friction stir lap welding(UaFSLW) was carried out to improve the quality of dissimilar Al/Mg alloys joint. The effects of ultrasonic power on the joint quality were also investigated.The results indicated that the larger effective lap width and mixing region between Mg and Al(Mg/Al MR) were attained by Zn foil addition and external ultrasonic assistance. Compared with the conventional joint, the finer and better-distributed Mg-Zn IMCs placing the continuous Al-Mg IMCs were formed in the Mg/Al MR of the Zn-added UaFSLW joint. The Zn foil addition and external ultrasonic assistance significantly improved the tensile shear load of the joint, and the load was increased with the increase of the ultrasonic power. The maximum tensile shear load of 7.95 kN was attained, which was 52.6% larger than that of the conventional joint.展开更多
The pure Zn foils with different thicknesses(0.02, 0.05, 0.1, 0.2 and 0.3 mm) were selected as interlayers to improve the quality of friction stir lap welding joint of 7075-T6 Al and AZ31 B Mg dissimilar alloys. The e...The pure Zn foils with different thicknesses(0.02, 0.05, 0.1, 0.2 and 0.3 mm) were selected as interlayers to improve the quality of friction stir lap welding joint of 7075-T6 Al and AZ31 B Mg dissimilar alloys. The effects of the interlayer thickness on joint formation, microstructure and tensile strength were analyzed. The results displayed that the maximum length of the boundary between stir zone(SZ) and thermo-mechanically affected zone in lower plate was obtained by the addition of the Zn interlayer with 0.05 mm thickness. The Mg–Zn intermetallic compounds(IMCs) were discontinuously distributed in the SZ, replacing the continuous Al–Mg IMCs. The size of Mg–Zn IMCs increased with the increase in the thickness of the Zn interlayer. The maximum tensile shear strength of 276 N mm-1 was obtained by the addition of 0.05 mm Zn foil, which increased by 45.6% of that of the joint without the Zn foil addition.展开更多
Friction stir brazing with ultrahigh rotation speed was applied to 6061 aluminium alloy–pure copper lap joints with the aid of zinc foil.The effects of different shoulder diameters from 7 to 15 mm on the microstructu...Friction stir brazing with ultrahigh rotation speed was applied to 6061 aluminium alloy–pure copper lap joints with the aid of zinc foil.The effects of different shoulder diameters from 7 to 15 mm on the microstructure and mechanical properties of Al/Cu FSB joints were investigated along with the temperature and resistance of the friction tool.The oscillation of forward resistance and lateral force was related to the flow of the plastic metal and contributed to obtain a good appearance during the welding process.From the appearance of the welded joints,it was obvious that the phase difference between the forward resistance and lateral force had a significant influence on the joint characteristics.Obvious scale-like ripples appeared on the weld area when a sharp angle in the phase difference curve existed.Additionally,with a lower axial force and oscillation assistance,a satisfactory joint could be obtained.The results of the shear strength of the brazed joint showed that the shoulder with a 12 mm diameter yielded the highest shear strength.Meanwhile,the zinc foil in the middle melted completely and formed finely dispersed CuZn5 Al–Zn eutectic structures at the Al–Cu interface.展开更多
基金supported by the National Natural Science Foundation of China (No. 51874201)
文摘The Zn-added ultrasonic assisted friction stir lap welding(UaFSLW) was carried out to improve the quality of dissimilar Al/Mg alloys joint. The effects of ultrasonic power on the joint quality were also investigated.The results indicated that the larger effective lap width and mixing region between Mg and Al(Mg/Al MR) were attained by Zn foil addition and external ultrasonic assistance. Compared with the conventional joint, the finer and better-distributed Mg-Zn IMCs placing the continuous Al-Mg IMCs were formed in the Mg/Al MR of the Zn-added UaFSLW joint. The Zn foil addition and external ultrasonic assistance significantly improved the tensile shear load of the joint, and the load was increased with the increase of the ultrasonic power. The maximum tensile shear load of 7.95 kN was attained, which was 52.6% larger than that of the conventional joint.
基金supported by the National Natural Science Foundation of China (No. 51874201)
文摘The pure Zn foils with different thicknesses(0.02, 0.05, 0.1, 0.2 and 0.3 mm) were selected as interlayers to improve the quality of friction stir lap welding joint of 7075-T6 Al and AZ31 B Mg dissimilar alloys. The effects of the interlayer thickness on joint formation, microstructure and tensile strength were analyzed. The results displayed that the maximum length of the boundary between stir zone(SZ) and thermo-mechanically affected zone in lower plate was obtained by the addition of the Zn interlayer with 0.05 mm thickness. The Mg–Zn intermetallic compounds(IMCs) were discontinuously distributed in the SZ, replacing the continuous Al–Mg IMCs. The size of Mg–Zn IMCs increased with the increase in the thickness of the Zn interlayer. The maximum tensile shear strength of 276 N mm-1 was obtained by the addition of 0.05 mm Zn foil, which increased by 45.6% of that of the joint without the Zn foil addition.
文摘Friction stir brazing with ultrahigh rotation speed was applied to 6061 aluminium alloy–pure copper lap joints with the aid of zinc foil.The effects of different shoulder diameters from 7 to 15 mm on the microstructure and mechanical properties of Al/Cu FSB joints were investigated along with the temperature and resistance of the friction tool.The oscillation of forward resistance and lateral force was related to the flow of the plastic metal and contributed to obtain a good appearance during the welding process.From the appearance of the welded joints,it was obvious that the phase difference between the forward resistance and lateral force had a significant influence on the joint characteristics.Obvious scale-like ripples appeared on the weld area when a sharp angle in the phase difference curve existed.Additionally,with a lower axial force and oscillation assistance,a satisfactory joint could be obtained.The results of the shear strength of the brazed joint showed that the shoulder with a 12 mm diameter yielded the highest shear strength.Meanwhile,the zinc foil in the middle melted completely and formed finely dispersed CuZn5 Al–Zn eutectic structures at the Al–Cu interface.
