7199

6705

كارشناسي ارشد

شناسايي و انتخاب مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1391

هفده، 107ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

فتح ا... كريم زاده، محمد حسن عباسي

10/8/91

محمد حسين عنايتي، حميدرضا سليمي جزي

1396/09/20

كتابنامه

مواد

مهندسي مواد

ID6705

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Improvement of tribological behavior of Ti6Al4V alloy by using thermal sprayed NbSi2 Al2O3 nanocomposite coatings Zohreh Yazdani Email address z yazdani@ma iut ac ir Date of Submission 10 9 2012 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M S Language Farsi Supervisor s Name Fathollah Karimzadeh Associate Professor karimzadeh f@cc iut ac ir Mohammad Hasan Abbasi Professor Abbasi32@cc iut ac irAbstractIn this study the NbSi2 Al2O3 ceramic matrix composite coating was thermally sprayed onTi6Al4V substrate to improve its tribological behavior So in the first step nanostructuredNbSi2 intermetallic compound and NbSi2 Al2O3 nanocomposite were produced viamechanical alloying MA The reached powders were evaluated by X ray diffractometry XRD scanning electron microscopy SEM microhardness test and heat treatment Thermodynamic analysis of these systems was carried out using semi empirical miedemamodel The obtained results were shown that NbSi2 intermetallic was formed in gradual modeat 60h of mechanical alloying of Nb Si powder mixture After the formation of thiscompound in the early stages of milling the Nb5Si3 intermetallic compound was also created Finally the reaction between Nb5Si3 and residual Si led to the formation of NbSi2 phase Thein situ NbSi2 Al2O3 nanocomposite was formed via mechanical alloying of Nb2O5 Al and Sipowders The reaction was completed in 40h of milling The results of the heat treatment ofpowder particles at 700 C showed that these compounds had good thermal stability Thepowders produced by mechanical alloying were agglomerated in order to gain the suitablesize for spraying Finally the agglomerated powders were coated on Ti6Al4V alloy byatmospheric plasma spraying method The characterization of coatings was performed usingx ray diffraction scanning electron microscope energy dispersive spectroscopy andmicrohardness indentation To measure the porosity of coating the image analyzer was used The results showed that in spite of growth of grain size and the decrease of internal latticestrain of nanostructured compounds the grain size of coating after thermal spray was still innanometer scale The achieved coatings were uniform and had good adhesion to substrate Also the value of hardness of nanocomposite coating was high and equal to 1100 HV Thetribological behavior of substrate and coatings was characterized by pin on disc method atroom temperature The results showed that the dominant mechanism of wear was abrasivewear High temperature oxidation behavior was studied using thermal analysis It showed thatnanocomposite coating can be used to protect Ti6Al4V substrate at 700 C KeywordsTi6Al4V Thermal spraying Nanocomposite Thermodynamic investigation NbSi2 Al2O3

فتح ا... كريم زاده، محمد حسن عباسي

محمد حسين عنايتي، حميدرضا سليمي جزي