| Aluminum-lithium alloy is one of the ideal materials that can meet the lightweight requirements of aerospace field,and it has the advantages of low dissimilarity,high-strength weldability and anti-fatigue crack.It is widely used in commercial,civil aircraft or helicopter,including skin,Fuselage frame,flap wing rib,horizontal stabilizer,tail stabilizer,door,inlet lip,fuel tank,so it is of great significance to improve the surface properties of aluminum-lithium alloys.In this paper,the anodic oxidation behavior of 2060-T8 aluminum-lithium alloy in sulfuric acid electrolyte and the behavior of micro arc oxidation of 2060-T8 aluminum-lithium alloy in silicate electrolyte were studied.Firstly,the effects of voltage,time and electrolyte concentration on the micro characteristics,adhesion performance and friction and wear properties of aluminum-lithium alloy anodic oxide films were analyzed on condition of direct current and voltage stabilization.Secondly,the effects of positive pulse voltage,time,duty cycle and pulse frequency on the micro characteristics,adhesion property and friction and wear properties of micro arc oxidation film were analyzed on condition of pulse current.In the sulfuric acid electrolyte,aluminum-lithium alloy is processed by constant voltage anodic oxidation.The surface of prepared oxidation film is gray,and there is no significant difference compared with aluminum-lithium alloy matrix.Through the analysis of SEM and EDS,it is found that the surface of the aluminum-lithium alloy anodic oxide film contains micro holes and cellular processes,and the surface is smooth.The film was mainly composed of Al,C O,S,etc..O and S are mainly derived from sulfuric acid electrolyte.In the silicate electrolyte,aluminum-lithium alloy is processed by single pulse micro-arc oxidation.The surface of prepared oxidation film is red brown,and the thicker prepared oxidation film is,deeper the color is.Through the analysis of SEM and EDS,the surface of the aluminum-lithium alloy micro arc oxidation film contains a large number of holes and cauliflower like protrusions,and the surface is rough.The film was mainly composed of Al,C O,Si,Na,etc..O,Si and Na are mainly derived from the silicate electrolyte.The tensile shear test shows that the bond property of anodic oxide film of Al-Li alloy is lower than that of micro-arc oxidation film.But both of them are higher than that of matrix alloy.During the process of anodic oxidation,when the concentration of sulfuric acid electrolyte is 10%,the bond strength of prepared aluminum-lithium alloy samples is highest,and the bond strength reaches up to 23.2MPa,73% higher than that of the matrix alloy.During the process of micro arc oxidation,when the the oxidation time is 45 min,the bond strength of prepared aluminum-lithium alloy samples is highest,and the bond strength reaches up to 28.2MPa,111% higher than that of the matrix alloy.The friction and wear tests show that the friction and wear properties of the micro arc oxidation film of Al-Li alloy are obviously higher than that of the anode oxide film,and the friction and wear properties of the anodic oxide film are higher than that of the matrix alloy.In the process of anodic oxidation,the friction and wear properties of Al-Li alloys increase firstly and then decrease with the increase of voltage.When the voltage is 10 V,the wear-resisting property of prepared anode oxide film is best,which is 7.2 times higher than that of the matrix alloy.In the process of micro arc oxidation,it is not conducive to improving the wear-resisting property if the positive pulse voltage is too high or too low.When the positive pulse voltage is 400 V,the wear-resisting property of prepared micro-arc oxidation film is best,and is 20 times higher than matrix alloy specimen. |
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