Research On Dissimilar Metal Re-melt Deposit Welding Of W-Cu-Al

In this paper, contrary to demand for W-Al welding,W-Al dissimilar metals re-melt deposit welding had been researched, in which copper was used as the intermediate layer.In the paper, Technical program that Cu was deposited on cylindrical W and Al was deposited at the surface of Cu-W had been designed.Copper was deposited at the surface of wolfram by W-Cu re-melt deposit welding,and the good proeess parameters were found. The average shear strength of W-Cu interface was 170MPa,and the sections were cut at the copper layer.Metallographic,observation of SEM and EDAX analysis indicated that, Because of the high wettability and creep relaxation of copper, penetration and diffusion of liquid copper occurred at the small range,in the micro-hole and channel at the surface of forging and PM W,which formed the W-Cu metallurgical bonding. Aluminum was deposited at the surface of copper by Cu-Al re-melt deposit welding,and the good proeess parameters were found. The average shear strength of W-Cu interface was 64MPa approximately, Reached 91.4% of pure aluminum body strength,and the sections were cut at the aluminum layer.Metallographic,observation of SEM and EDAX analysis indicated that, Cu-Al metallurgical bonding is formed by the melt and diffusion of Cu at interface,which lately reacted with Al generating a+9 tissue.Copper was deposited at the surface of wolfram by W-Cu re-melt deposit welding, processing copper interlayer at a thickness of about 1-2mm on the surface of W. On this basis, the good re-melt deposit welding parameters of cylindrical W-Cu-Al were found: protective agent is 75% LiCl+10% LiF+15% ZnCl2; using WH-VI-50 IGBT high frequency of 32kHz induction heating power supply, with the minimum heating power (oscillation current 260A), heating time 45-50s; when welding was finished workpiece cooled down in the wet sand in 10-15s, then went on cooled down with the furnace onset temperature to 350℃. Metallographic,observation of SEM and EDAX analysis indicated that, on W-Cu-Al composite welding interface, W-Cu interface unchanged,while a+0 tissue reacted by Cu and Al was built at transition layer of CuAl.The average shear strength of W-Cu-Al interface was 55MPa approximately, while maximum shear strength get to 70MPa,and the sections were cut at the aluminum layer.