بررسي تجربي و عددي سايش درماده نانو ساختار NiAl

چكيده انگليسي :

88Experimental and Numerical Investigation of Wear in Nanostructured NiAl Material Hamideh Tavousi h tavousi@me iut ac ir Date of Submission 2014 01 18 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Saeed Ziaei Rad szrad@cc iut ac irAbstractWear is one of the destructive mechanisms which can deteriorate performance of many systems such assliding components and gears in automobiles airplanes and pumps It causes the reduction of componentlife and reliability The study of wear in nano materials is more important than other conventional materials due to high surface to volume ratio and effect of parameters such as grain size grain boundary dislocationdensity and porosity on mechanical properties in nano scale NiAl intermetallic is being recognized as a high temperature structural material because of its excellentoxidation resistance high thermal conductivity low density and high melting point These properties havemade NiAl a suitable material for coating different industrial components such as gas turbin engine rotorblade and stator vanes to improve their wearing corrosion and oxidation resistance A number of attemptshave been made to overcome this draw back One of the possible routes is nanocrystallization of NiAlwhich may transform nominally brittle compound into a ductile material In this work NanocrystallineNiAl powder was prepared by mechanical alloying and deposited on low carbon steel substrates by usinghigh velocity oxygen fuel HVOF technique Then nanoindentation test was carried out using diamond Berkovich indenter to find out the mechanicaland surface properties of the coating such as hardness Young s module and Poisson ratio Next the weartests were performed with a pin on block machine without lubrication under different load conditions inorder to find out friction and wear behavior Moreover Global Incremental wear model GIWM and finite element technique were used to model thewear characteristics of the nanostructured material GIWM was an incremental implementation ofArchard s wear model on the global scale for pin wear and block wear in a pin on block tribometer Also this work presented a computational study based on the linear Archard s wear law and finite elementmodeling FEM in order to analyze unlubricated sliding wear Such modeling was developed using finiteelement software Abaqus with 2 D and 3 D deformable geometries and elastic material behavior for thecontact surfaces in pin on block experiments Archard s wear model was implemented into a FORTRANuser subroutine UMESHMOTION in order to describe sliding wear Such implementation considered anincremental computation for surface wear based on the nodal displacements by means of adaptive meshtools that rearrange local nodal positions In this way the worn track was obtained and new surface profilewas integrated for mass loss assessments The results indicated that GIWM was an approximate method and predicted pin on disc experiments to alimited extent but it was a valid method for nanostructured materials with low wear coefficient The resultsof FEM show that the volume losses obtained with the numerical analysis seem to be in good agreementwith the experimental ones Keywords Wear Nanostructured NiAl coating Pin on block test Wear simulation

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بررسي تجربي و عددي سايش درماده نانو ساختار NiAl

پوشش نانو ساختار نيكل آلومينيوم , آزمايش پين روي ديسك