| Lightweight is a very important direction,and the use of lightweight materials is an important way for lightweight development in modern industry.The advantages of plastic are lightweight,high corrosion resistance,and excellent mechanical properties.Therefore,it is very important to study the connection technology between plastic and metal material.Aluminum alloy is one of the lighter metal materials.At present,the connection methods of aluminum alloy and plastic mainly include bolt connection,riveting,glue connection,injection molding connection and welding.The holes of bolted connection and riveting are prone to result in stress concentration,the impact resistance and peeling strength of the glued interface are low,the connection strength of injection molding is limited,and the high degree of automation in welding.Among them,the significant advantages of ultrasonic welding are short connection time and low cost.Therefore,this subject investigated the ultrasonic welding technology and craft of 6063 aluminum alloy and polyphenylene sulfide(PPS).This paper studied the effect of ultrasonic welding process parameters,aluminum alloy surface pretreatment process,and other factors on the connection strength of the joint,determined the feasible connection technology,and obtained the optimal process parameters through orthogonal experiments.The surface of 6063 aluminum alloy and the joint of 6063 aluminum alloy and PPS were analyzed through the scanning electron microscope,X-ray photoelectron spectrometer,and Fourier transform infrared spectrometer to study the connection mechanism.The research results showed that the ultrasonic amplitude and welding pressure were the key process parameters during ultrasonic welding.The shear strength of the joint firstly increased and then decreased with the increase of the ultrasonic amplitude,welding pressure,and welding time.However,the shear strength of the joint remained constant when the holding pressure time after welding was extended to a certain time.The optimum ultrasonic welding process parameters obtained by orthogonal experiments were that the ultrasonic amplitude was 55 ?m,the welding pressure was0.6 MPa,the welding time was 6 s,and the pressure holding time after welding was 4s.Among the anodic oxidation process parameters,oxidation temperature and oxidation voltage were the main influencing factors.With the increase of oxidation temperature,oxidation time,oxidation voltage,and electrolyte concentration,the shear strength of the joint first increased and then decreased.The optimal combination of process parameters obtained by orthogonal experiment was: oxidation temperature was50 ?,oxidation time was 40 min,oxidation voltage was 25 V,and electrolyte concentration was 20 wt%.The surface treatment process of 6063 aluminum alloy was the key process to obtain high-strength joints.After 6063 aluminum alloy was anodized,the maximum shear strength of 6063 aluminum alloy/PPS joint was 17.09 MPa,which was 12.18 times more than that of the non-anodic oxidation treatment.The joint shear strength could reach 24.85 MPa when the aluminum alloy surface was treated by anodic oxidation and silane coupling agent KH-560.The main failure mode of the 6063 aluminum alloy and PPS plastic joint without anodizing treatment was interface cracking,and the interface was only connected by weak adhesion.After anodizing treatment,a porous structure was generated on the surface of 6063 aluminum alloy.Besides,the molten PPS plastic was injected into the micropores on the surface of 6063 aluminum alloy under the effect of ultrasonic flow to form a mechanical anchoring structure,which greatly improved the connection strength of the joint.The failure mode of the joint was mixed form consisted of cohesive fracture and interface cracking of PPS.After the surface treatment of the anodic oxidation test and silane coupling agent KH-560,a large number of hydroxyl groups(-OH)were formed on the surface of 6063 aluminum alloy,which reacted with KH-560 to form Al-O-Si chemical bonds.Meanwhile,a silane film was formed on the surface of the aluminum alloy.During ultrasonic connection,the epoxy-functional group on KH-560 reacted with the sulfhydryl(-SH)on PPS to form a C-O-S chemical bond,which effectively improved the shear strength of the 6063 aluminum alloy/PPS joint.At this time,the failure mode of the joint was mainly the cohesive fracture of the PPS at the interface. |
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