Liming Liu

Laser weld bonding of A6061Al alloy to AZ31B Mg alloy

Abstract A new welding technique called laser continuous weld bonding (referred to as LWB) has been put forward beyond laser welding and adhesive bonding in the present paper. A6061Al and AZ31BMg were joined successfully by LWB. The results have showed that LWB joints exhibit better properties than those made by laser welding and adhesive bonding only, because of the composite functions between laser welding and adhesive bonding. Using proper welding parameters, a favourable metal fusion that contained less residue owing to adhesive gasification could be gained. Intermetallic compounds composed of the phases such as Al3Mg2 and Al12Mg17 were detected. The area of the incomplete combustion was narrow and only a small part of the adhesive layer was affected, so the effect on the quality of LWB was small.

Study on Mg/Al Weld Seam Based on Zn–Mg–Al Ternary Alloy

Based on the idea of alloying welding seams, a series of Zn–xAl filler metals was calculated and designed for joining Mg/Al dissimilar metals by gas tungsten arc (GTA) welding. An infrared thermography system was used to measure the temperature of the welding pool during the welding process to investigate the solidification process. It was found that the mechanical properties of the welded joints were improved with the increasing of the Al content in the Zn–xAl filler metals, and when Zn–30Al was used as the filler metal, the ultimate tensile strength could reach a maximum of 120 MPa. The reason for the average tensile strength of the joint increasing was that the weak zone of the joint using Zn–30Al filler metal was generated primarily by α-Al instead of MgZn2. When Zn–40Al was used as the filler metal, a new transition zone, about 20 μm-wide, appeared in the edge of the fusion zone near the Mg base metal. Due to the transition zones consisting of MgZn2- and Al-based solid solution, the mechanical property of the joints was deteriorated.

Analysis of energy utilisation efficiency in laser–GTA hybrid welding process

Abstract The effect of welding parameters on energy utilisation efficiency in laser–gas tungsten arc (GTA) hybrid welding process is investigated. Then, optimum butt joints are made by laser welding, GTA welding and laser–GTA hybrid welding, and the energy consumption in each process is calculated and compared. Both plasma and keyhole behaviours are studied. Results indicate that the parameter Dla greatly affects the energy utilisation efficiency in hybrid welding. The reason is that Dla determines keyhole behaviour and laser induced plasma, and these determine the coupling discharge of laser induced and GTA plasmas. Compared with laser and GTA welding, hybrid welding is more energy efficient.