Study On The Effect About The Performance Of7050Aluminum Alloy With Multi-scale Structure On Surface

Material with multi-scale structure on the surface has the good performance in self-cleaning, hydrophobicity and anti-adherence. There will be vulcanization pollutants which residual on the rubber mould. In order to improve the anti-adherence ability of rubber mould, multi-scale structure was chosen to build on the surface. In this research the shot penning device was chosen to build the multi-scale structure on the aluminum alloy surface. The effect of the multi-scale structure forming process by shot penning process parameters including shot peening pressure, duration time, diameter of projectiles and so on were discussed. The performance of the surface after multiple shot penning was researched. The method could be used to improve the anti-adherence performance of the surface of the mould. The main research contents about this paper are as follows:1. By adjusting the shot penning process parameters including shot peening pressure, duration time, diameter of projectiles and so on, the multi-scale structure could be established on the surface of material. It can be seen that convex-concave’s diameter at micrometer level is smaller than that of the larger diameter of projectiles for shot penning at first time by observing the surface of the test samples. At the same time the structure is less deeper if they use the longer duration time and less pressure for shot penning. Convex-concave’s diameter at micrometer level is larger than that uses the smaller diameter of projectiles for shot penning at first time. The sample which shot penning pressure at0.25MPa, diameter of projectiles is0.3mm, duration time is5min has the least convex-concave at nanometer level. The roughness is high if the shot penning process uses the larger diameter projectiles at the first time.2. After shot penning, friction and wear resistance performance of the material was researched. Results indicate that on oil lubrication condition, friction factor is lower than that of the original sample. And the shot penning process parameter of the lowest Friction factor is0.2MPa pressure, diameter of projectile is0.8mm, and the duration time is5min, And the shot penning process parameter of the highest Friction factor is 0.25MPa pressure, diameter of projectile is0.3mm, and the duration time is5min. On the non lubrication condition, the friction factor of shot penning treatment sample is lower than the original one at first and ends at the same level, the test samples which use the larger diameter of projectiles for shot penning at first time is at abrasive wear situation, and others at the mix situation between adhesive wear and abrasive wear, especially the one uses the lower pressure and less duration time is at adhesive wear situation. Hardness of the surface is200HV after multiple shot penning. And the thickness of surface deformation layer is20μm.3. Flat vulcanizing experimental result show that:the multi-scale structure that formed in the surface after shot penning can reduce the activity of the test sample. The test sample with multi-scale structure also gets a improvement in hardness and reduces in friction factor, which can improve the demould ability. After vulcanization it will reduce the pollutant in the surface. Self-cleaning ability is improved with the decrease of wettability. At the same time the multi-scale structure in the surface can adsorption the air, and reducing the contact area between the surface of the test sample and rubber, and then improve the anti-adherence ability.