6923

6465

كارشناسي ارشد

مهندسي مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي مواد

1390

پانزده، 72ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

مرتضي شمعانيان، محمدحسين عنايتي

14/5/91

رحمت ا... عمادي، حميدرضا سليمي

1396/09/18

كتابنامه

مواد

مهندسي مواد

ID6465

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Fabrication and Characterization of Nanocomposite Intermetallic Ti Al Coating by Means of Mechanical Alloying Parisa Ashtijoo Email address p ashtijoo@ma iut ac ir Date of Submission 4 March 2012 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor s Name Morteza Shamanian Associate Professor shamanian@cc iut ac ir Mohammad Hossein Enayati Associate Professor ena78@cc iut ac irAbstractIn the current investigation mechanical alloying technique was utilized to produce a nanocompositeTiAl TiC TiAl2C coating on Ti substrate Poor wear resistance and low hardness of Ti hinder its furtherapplication Fabrication of high resistance coating on Ti substrate is one of the beneficial ways to improve itstrybological properties TiAl intermetallic compounds are noteworthy because of high oxidation resistanceand good mechanical properties One of the most promising methods recently utilized for coating ismechanical alloying The coating process along with mechanical alloying was the results of repetitive coldwelding and fracturing of powder particles with each other and with hard specimen surface due to ball powder substrate impacts Three approaches were considered to fabricate TiAl 20 wt stoichiometriccomposition First Mechanical alloying of Ti Al C Second Mechanical alloying of Ti Al TiC and at lastMechanical alloying of Ti Al C powder in planetary ball mill for 70 hours In this study milling time ball topowder ratio BPR and ball size on thickness hardness and coating morphology was examined The samplesmilled for different time were subjected to heat treatment at 900 C for 90 min in vacuum furnace In thisregard X ray diffraction XRD analysis scanning electron microscopy SEM and energy dispersive X rayspectroscopy EDS were employed to investigate phase transformation microstructural and morphologicalevolutions Microhardness and roughness were also used to characterize mechanical properties of the coating As the result of first method the best coating was formed by 4mm ball size and BPR of 10 1 whichincreasing in ball size and BPR led to formation of non uniform coating The final grain size of 12 h milledsample was estimated to be around 18 nm Hardness and coating thickness was increased by increasingmilling time which they reached 460 HV and 43 m respectively Roughness also decreased by milling time Nano Scale AlTi2C AlTi2 and TiC phases were detected after heat treatment The approximate grain sizes ofAlTi2C and AlTi2 after 12 h of milling was 35 nm while that of TiC phase was about 20 nm Hardness androughness of coating surface also increased after heat treatment In the second approach TiC particles led tothe formation of non dense coating specially in the first stages of milling The roughness and hardnessincreased due to increasing in mechanical alloying time Al3Ti TiC AlTi2C nanocomposite coating formed inthe first stage of milling and AlTi2 TiC AlTi2C nanocomposite coating was detected by increasing in millingtime In third method Al Ti C powder was milled by planetary ball mill for 70 hours and then coated on Tisub layer Because of the presence of brittle powder coating morphology was non uniform and dense Keywords Mechanical alloying coating intermetallic compounds nanocomposite

مرتضي شمعانيان، محمدحسين عنايتي

رحمت ا... عمادي، حميدرضا سليمي