Study On Cavitation Erosion Performance Of AlSi10Mg

Cavitation which is relevant to pressure changes,occurs inside of the liquid and includes the generation,enlargement and collapse of bubbles.Cavitation erosion is the damage and destruction of solid material caused by cavitation.With regard to hydraulic components and water conservancy facilities which work in liquid,the surface material is vulnerable to cavitation erosion.AlSilOMg is a kind of aluminum alloy with high abrasion and erosion resistance,small coefficient of thermal expansion,high strength and stifness and high thermal conductivity.The advantages contribute to its extensive applications.However,the study on cavitation erosion performance of AlSilOMg is rather rare.It is necessary to investigate the cavitation erosion performance of AlSilOMg for its application in liquid condition.The first chapter introduces these following information that the physical background of cavitation and cavitation erosion,the Standard Test Method for Erosion of Solid Materials by a Cavitating Liquid Jet,the influences and mechanisms of surface topography upon cavitation erosion and the selective laser melting technology with its researches and applications on aluminum alloy.Finally,the research contents are determined.The second chapter introduces the test rig based on ASTM G134.The standard nozzles of cavitating jet test are manufactured.The test facilities used to analyzing surface topography,hardness,density,phase composition and metallographic phase are presented.The third chapter investigates how the surface topographies caused by different finishing surface processing methods influence the cavitation erosion of forging AlSi10Mg samples.These following results are obtained:the mass losses of laser texturing and turning samples whose surfaces are rougher,are larger than that of polishing and grinding samples;because of a kind of similar topography shared by laser texturing and turning samples,plastic deformations are observed in these samples;when the manufacturing traces disappear now can be predicted by means of 3D surface height parameter analysis.The fourth chapter investigates how the different laser scanning speed during SLM process influences the cavitation erosion of AlSilOMg samples.These following results are obtained:because of residual alloy particles in pores,during the accelerating period the mass losses of SLM samples are much bigger than that of forging samples;inappropriate laser scanning speed can aggravate the topographical flaws which bring about larger mass losses and loss rates;during the steady period,the mass loss rates of SLM samples are much smaller than that of forging samples;the metallographic photographs of SLM samples show very fine cellular-dendritic structures which improve the cavitation resistance and hardness of SLM samples.The fifth chapter summarizes the main works and achievements of this research.In the future there are still some works in these field to be done.