Study On Ultrasonic Welding Of Aluminum And Titanium Dissimilar Alloy

This paper mainly studied the ultrasonic metal welding of aluminum alloy and titanium alloy.Ultrasonic metal welding as a solid state welding technology,which can relalize the connection of metal with the combined effect of clamping pressure and ultrasonic vibration.Because of there is no current in the welding process,it has the characteristics of low temperature,low pressure,low energy consumption,which can achieve a good connection of aluminum alloy and titanium alloy.Firstly,by building a platform of ultrasonic welding,the effect of welding energy,welding amplitude,welding pressure and natural aging on the quality of Al-Ti ultrasonic welding joints were studied.The results reveal that the parameters of ultrasonic 1mm Al6061-O aluminum alloy and 0.4mm Ti6Al4V titanium alloy welding were:welding pressure（0.241MPa,0.621MPa）,welding amplitude（50μm,90μm）,welding energy（500J,900J）;The optimal combination of the welding parameters was 0.552MPa,70μm,900J;Natural aging can improve the mechanical properties of welded joint significantly.Secondly the parameters of aluminum-titanium ultrasonic metal welding were optimized by L₂₇ orthogonal test.The results reveal that the welding energy,amplitude and pressure on joints have significant effect on the maximumtensile load of welding joints;and the effect order,energy>amplitude>pressure;however,the effect of their interaction can be neglected;the contribution rate of welding energy,welding amplitude,welding pressure and error to the joint maximum tensile load were 86%,8%,4%,2%,respectively;the maximum tensile load process parameters were A₃B₂C₂,950J（welding energy）,75μm（welding amplitude）,0.552psi（weling pressure）（A₃B₂C₂）;and the most robust tensile load process parameters were A₁B₁C₃,900J（welding energy）,70μm（welding amplitude）,0.621psi（weling pressure）.Finally,we selected pure aluminum powder as interlayer to strengthen the quality of the welding joint of 1 mm Al6061 aluminum alloy and 0.4 mm Ti6Al4V titanium alloy.The results reveal that selecting pure aluminum powder as the interlayer of ultrasonic welding of the aluminum alloy and titanium alloy can effectively improve the quality of the welded joints;The main effect of the interlayer:（1）the interlayer can effectively remove the oxide film on the metals,leading to the metal bonding of the fresh metal surface;（2）the interlayer can improve the interface roughness,result in generating more heat and plastic deformation on the metal interface,thus leading to the welding interface connected closely.