Effect Of Solution And Aging Treatment On Microstructure And Mechanical Properties Of AZ91Magnesium Welding Joint

The magnesium alloy based on magnesium and added other elements.Itscharacteristics are: low density, high strength, elastic modulus,good vibration resistance,ability to withstand shock loading better than aluminum, good alkali-resistant organismsand corrosion. The main alloy elements are aluminum, zinc, manganese, cerium, thoriumor a small amount of cadmium and zirconium. Currently the most widely used is Mg-Alalloy, followed by it are Mg-Mn and Mg-Zn-Zr. It mainly applied into aviation, aerospace,transportation, chemical, rocket and other industrial sectors. According to molding methodis divided into two kinds: wrought magnesium alloys and cast magnesium alloys. In thecast magnesium alloy field, its application has been widely developed but poor magnesiumalloy welding has faced bottleneckt. It easily forms cracks, porosity, oxide slag weldingdefects after welding. Heat treatment method used to be a necessary procedures onmagnesium alloy.In recent decades, a large number of experiments show that heattreatment can improve the overall performance of magnesium alloys, especially the heattreatment of cast magnesium alloy and magnesium alloy and heat treatment process duringdeformation. While few heat treatment of welded joints studies, the paper aim to seek toimprove the optimum parameters of magnesium alloy welded joints by using solution andaging treatment(T6).This paper analyses the influence of different technological parameters on themicrostructure and mechanical properties of welded joint by ueing T6. Experimentalwelding current, welding speed and ventilation are optimal experimental parameters, theydo not perform multivariate analysis.Through different T6process parameters on weld, theoptimal parameters of better joints mechanical properties and microstructure can beselected. After welding, the stretching, hardness experiments have been done for samples.optical microscopy and scanning electron microscopy (SEM) were used to examine themechnical properties, microstructure of welded joint of AZ91magnesium alloy. Conclusions show that solution and aging have a major impact on the microstructureand mechanical properties of AZ91magnesium alloy.A better solution and agingparameters can change the mechanical properties of the material. The best soluteparameters:420℃,15hours, material microstructure and mechanical properties is thebest:σb=274.28MPa, Ψ=13.04%,. Best solution and aging parameters200℃,10hours,the mechanical properties of the optimal: σb=300.92MPa.