Study On The Joining Between Magnesium Alloy And Macromolecular Materials

As a reconsidered engineer material, magnesium alloy has been widely used in the fieldof automobile manufacture, spaceflight and electron industry. The industrial applications ofthe material are closely linked with the development of joining techniques. Nowadays, thejoining technique of magnesium alloy has developed rapidly. However, with the increased useof magnesium in manufacture, the joining technique of magnesium alloy and other materialhas been the key problem for its application. Macromolecule material is also used widely inthe fields of automobile, electron and micro-technology. The joining of magnesium alloy andmacromolecule will attract the attentions of people. Under this background, the weldability ofmagnesium alloy and macromolecule is studied in this article.Low-power YAG laser is used to weld polypropylene and the welded joint with highquality is obtained successfully. The absorptivity of laser beam is improved due to the surfacetreating. Through the welding process of polypropylene, the optimal welding parameters areobtained. The experimental results indicate that the tensile strength of the welded joint is closeto that of base material. It proves the feasibility of laser welding of polypropylene andestablishes the basis for the welding of magnesium alloy and plastic.Laser welding of dissimilar magnesium and macromolecule is first brought forward. Theappearance of the joint, element distribution, joining mechanism and mechanical propertiesare analyzed in the study. A stake weld joint is acquired between magnesium andmacromolecule, without any pore or inclusion. The existence of ester carbonyl group in thejoint of magnesium to polypropylene confirms the formation of metal complex. The forces ofchemical bond which exist in the metal complex ensure the joining stable between magnesiumand polypropylene. The shear strength of the joint reaches 79.3% of polypropylene basematerial.The joining between magnesium alloys and macromolecule (PP, ABS) is realized byadhesive bonding. A good bonding is acquired by optimums technique. The adhesive layerappearance, mechanical properties and failure forms are researched in different bondingcondition. In order to improve adhesive strength, SiO₂ is mixed into adhesives. The tensilesheafing test of SiO₂ doped specimen reveals that the adhesive strength is higher than the base metal. Analysis of the adhesion mechanism leads to a conclusion that magnesium bonding ismainly the result of coordinative bond forces.