Investigation On Microstructures And Properties Reinforced Of Magnesium Alloy Surface Layer By High Energy Milling Ultrafine Powder

Magnesium alloy is one of the most widely used metal materials.But its poor corrosion resistance,low wear resistance and other problem,has been greatly restricted the development of magnesium alloy.Some studies show that most of the magnesium alloy corrosion and wear phenomenon happen in the surface.A lot of methods for the process,but they exist some issues such as high cost,pollution,complex process and so on.This study show a new method of magnesium alloy surface treatment.This process is low cost,simple technique.According to the theory of MCP and atomic diffusion,through the high energy of ultrafine powder grinding,melting a Diffusion-fusion layer in AZ31 magnesium alloy surface.The main research contents includs:ultrafine powder process,substrate surface of sample pretreatment,high energy milling process,design orthogonal experiment to conclude that the main influence factors,optimization of process parameters,etc.Using SEM,EDS and XRD methods to analysis the morphology of meit layer,compontent content and distribution characterized;Adopts full immersion test and electrochemical test to analysis expansion of melting layer corrosion resistance;Reciprocating sliding friction experiment to carry out the surface of the sample and the analysis of the change of the test before and after wear;expanding the influence degree of the Diffusion-fusion layer;Through the morphology analysis of AZ31 magnesium alloy surface wear mechanism and expansion of Diffusion-fusion layer on its friction.The results show that the diffusion effect due to mechanical force chemistry and material interaction,make ultrafine powders in the magnesium alloy surface form relatively smooth expansion of Diffusion-fusion layer,the thickness of Diffusion-fusion layer can be up to75?m.In the expansion of the Diffusion-fusion layer has Al_0.403Zn_0.597,Al₁₂Mg₁₇ phase generated.Due to existence of the expansion of Diffusion-fusion layer makes magnesium alloy from corrosion potential increased 0.14V.At the same time,the Diffusion-fusion layer effectively improve the magnesium alloy surface wear resistance.On the analysis of the expansion of Diffusion-fusion layer formation mechanism research,for subsequent performance,more excellent ceramic passivation membrane is prepared to provide the important reference value and technical support.