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冷喷涂7075铝合金微观组织和力学性能研究.docx

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冷喷涂7075铝合金微观组织和力学性能研究 摘要 本文研究了冷喷涂7075铝合金的微观组织和力学性能。结果表明，冷喷涂7075铝合金的显微组织主要由等轴晶和柱状晶组成，晶粒尺寸小于10μm。随着冷喷涂厚度的增加，晶粒尺寸呈现出逐渐增大的趋势。冷喷涂后7075铝合金的硬度和拉伸强度均有所提高，而延伸率略微降低。本研究结果对于深入了解冷喷涂7075铝合金的微观结构和力学性能具有重要意义。 关键词：冷喷涂，7075铝合金，微观组织，力学性能 Introduction Coldspraycoatingisanewsurfaceengineeringtechnologythatcanimprovetheperformanceofmetallicmaterialsbyformingacoatingwithexcellentmechanical,wearandcorrosionproperties.Aluminumalloysarewidelyusedinaerospace,transportationandotherfieldsduetotheirhighstrength-to-weightratioandgoodcorrosionresistance.Amongthem,7075aluminumalloyisahigh-strengthaluminumalloywithgoodtoughnessandcorrosionresistance,whichiscommonlyusedinaircraftstructuralpartsandmissilecomponents.However,duetothelimitationsoftraditionalmanufacturingprocesses,thesurfaceof7075aluminumalloypartsispronetowear,corrosionanddeformationunderharshworkingconditions,resultinginlowerreliabilityandservicelife.Therefore,itisurgenttodevelopnewsurfaceengineeringmethodstoimprovetheperformanceof7075aluminumalloy. Coldspraycoatingisapromisingsurfaceengineeringtechnologyduetoitslowtemperature,nothermaldamageandhighdepositionefficiency.Intheprocessofcoldspraycoating,thegasflowisacceleratedtohigh-speedsupersonicflow,andthesolidpowdermaterialisacceleratedtothespeedof1000m/sorevenhigher,andthenthepowderparticlesareimpactedonthesubstratesurfacewithhighkineticenergy,formingadensecoatinglayer.Coldspraycoatinghastheadvantagesofhighadhesionstrength,lowporosity,finemicrostructureandhighhardness. Inthisstudy,coldspraycoatingtechnologywasusedtodeposit7075aluminumalloypowderonthesurfaceof7075aluminumalloysubstrates.Themicrostructureandmechanicalpropertiesofthecoldspraycoatedsampleswerestudiedbyopticalmicroscopy,scanningelectronmicroscopy,X-raydiffractionandmechanicaltesting. Experimentalprocedures Theexperimentalmaterialswere7075aluminumalloypowderand7075aluminumalloysubstrates.Thesizeofthealuminumalloypowderwasbetween10and40microns,andthepuritywas99%.Thesizeofthealuminumalloysubstrateswas100mm×100mm×10mm.Thecolds