| With the development of additive manufacturing technology,laser cladding deposition technology has been widely applied in the field of aerospace repair due to its advantages of selective local fine repair,high cladding quality,low cost and energy consumption,and has quickly become a strategic technology that changes the traditional manufacturing method of parts in the aerospace field.In the aviation field,the micro motion damage of aircraft engine components directly affects the operational safety of aircraft.In the aviation field,the micro motion damage of aircraft engine components directly affects the operational safety of aircraft.As a key component of aviation engine power and energy equipment,nickel based high-temperature blades are prone to micro wear and tear when working in extreme environments for a long time,leading to crack initiation and propagation,leading to blade fracture and failure.This greatly reduces the safety of in-service flight components and poses a serious safety problem for the aircraft.Therefore,exploring the micro wear characteristics of laser cladding deposited nickel based alloys is of great significance for the safe service of repaired aircraft engines.In this thesis,Inconel 718 alloy prepared by laser cladding deposition technology was chosen to be studied.Using a self-developed multifunctional composite fretting wear testing machine,tangential fretting wear tests were conducted in a ball plane point contact mode,revealing the fretting wear characteristics of Inconel718 alloy prepared by laser cladding deposition under different fretting factors.The main results obtained are as follows:(1)The experimental results under different micro displacement and load showed that when the displacement amplitude remained constant,the normal load increased from F_n=10N to F_n=50N,and the fretting running state changed from gross slip regime(GSR)to mixed slip regime(MSR),gradually intensifying the wear damage of the material.When the normal load remains constant,as the displacement amplitude increases from D=100μm to D=200μm.The area of fretting damage increases.The evolution law of sample damage mainly manifests as the appearance of initial large delamination and block shaped debris,followed by the initiation and propagation of cracks,the peeling and fragmentation of block shaped debris,and the formation of a large number of small debris.The main wear mechanisms are fatigue wear,oxidation wear,and abrasive wear.(2)The test results at different test temperatures showed that the displacement amplitude D=15μm,the fretting is in a partial slip regime(PSR).As the experimental temperature increases,the mechanism of fretting wear mainly ranges from elastic-plastic deformation and abrasive wear to fatigue spalling,adhesive wear,and oxidation wear,resulting in an increase in material wear damage.At displacement amplitude D=100μm.The fretting running state is affected by the test temperature.As the test temperature increases,the fretting running state changes from GSR to MSR.At high temperatures,an adhesive layer is formed in the contact area that has the effect of reducing friction damage,slowing down the fretting wear damage of the material.(3)The experimental results under different cycles showed that at room temperature(RT),as the number of cycles increased,the fretting running state gradually changed from MSR to GSR.A large number of delaminations and fatigue cracks appear on the worn surface,and the wear damage of the material gradually intensifies.The damage during fretting wear is mainly caused by fatigue cracking or peeling of the material surface,supplemented by surface oxidation damage,plastic deformation,and thermal deformation.At a high temperature of T=400℃,the fretting running state is MSR.As the number of cycles increases,fretting at high temperatures can lead to frictional oxidation and plastic deformation of the material.The contact area exhibits severe plastic deformation and mutual adhesion of wear debris. |
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