Investigation of Friction Weldability of En Aw 6063 Aluminium Alloy Tube to Tube Plate Using an External Tool
The traditional welding methods are commonly used tube to tube plate of heat exchangers and economiser. In this study it was investigated that application of an alternative welding method which called friction welding of tube to tube plate by using an external tool was used joining of AlMg0,7Si (EN AW 6063) aluminium alloy. The AlMg0,7Si plates with dimensions 5x50x70 mm were drilled Ø20,5, Ø21, Ø21,5, Ø22 mm. The four different sizes AlMg0,7Si tubes with dimensions 2 mm wall thickness, 20 mm outer diameter, respectively 45,5, 46, 46,5, and 47 mm length friction welded to plate using an external tool (FWTPET) at constant 900 min-1 tool rotational speed. The vertical force between tool shoulder and tube was constant during the welding, and temperature was measured at every different welding parameters. The shear test was done for determining for welded joints using special fixture. Shear strength of welded joints were determined depend on welding parameters
Interfacial Microstructure and Strength of Friction Welding of Steel Tube to Aluminium Tube Plate Using an External Tool
Joining of dissimilar materials is of increasing interest for a wide range of industrial applications like nuclear, thermal power. The automotive industry, in particular, views dissimilar materials joining as a gateway for the implementation of lightweight materials. Friction welding of tube to tube plate using an external tool is an innovative friction welding process and is capable of producing high quality leak proof weld joints. In the present study, friction welding of steel tube to commercial aluminum tube plate using an external tool with and without tube projection have been performed. The joints were evaluated by mechanical testing and metallurgical analysis. The results of bonding interface hardness and joint strength reveal that steel tube with projection are better than the steel tube without projection.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.