15530

1566

دكتري

مهندسي مواد

اصفهان : دانشگاه صنعتي اصفهان

1398

ط، 116، [17]ص.:مصور،‌ جدول، ‌نمودار

مهدي صالحي

عباس بهرامي

محمود منيرواقفي، بهروز موحدي، ابوذر طاهري زاده

1399/02/13

كتابنامه

مهندسي مواد

پرديس

1399/02/13

13822422

Fabrication microstructural characterization and mechanical properties evaluation of Ti TiB TiB2 composite coatings deposited on Ti6Al4V alloy by Electro Spark Deposition Method Hassan Shafyei Hassan shafyei@gmail com Date of Submission 2020 2 14 Materials Engineering Group Pardis College Isfahan University of Technology Isfahan 84156 83111 Degree PhD Language FarsiSupervisor Mehdi Salehi salehi@hotmail co ukAdvisor Abbas Bahrami a n bahrami@cc iut ac irAbstractIn this study briquettes of Ti TiB TiB2 composite were produced by mixing Ti and B powders performing self propagating high temperature synthesis process and by applying hydrostaticpressure on the reaction products with a high capacity press Ti TiB TiB2 was then coated toTi6Al4V substrate by Electro Spark Deposition ESD technique under two atmospheres of airand argon single and double layer coatings and in two energy levels of 40 W and 110 W asinput powers Coatings microstructure were examined by Scanning Electron Microscope SEM equipped with Energy Dispersive Spectroscopy EDS analyzer Comparison of the coatingsmicrostructure with the electrode microstructure shows that the coatings have a much finermicrostructure than that of the electrode due mainly to the high solidification rate in the ESDprocess Microstructural observations also revealed that the main phases in the coatings areneedleshaped TiB and particle shaped TiB2 in the Ti matrix The coating microstructure wasmuch finer due to an increase in solidification rate by reducing the input power from 110 to 40W In such a situation two phases of TiB2 and TiB with nanometer sizes were scattered in the Timatrix Also due to the trapping of the gases in low input power of 40 W a limited number ofvery small gas pores was created in the microstructure Interface examination of the coating andthe substrate by the Line Scan and X ray Image show a good coherence of the coating with thesubstrate Adhesion results showed that the bond strength between the coating and the substratewas higher than 50 MPa in all coatings No crack was observed in the coatings after bendingtests which were performed in accordance with the intended standard on the samples around amandrel The hardness of all coatings was increased with decreasing the input energy from 110to 40 W Keywords Ti TiB TiB2 MMC coating Microstructural Mechanical properties Electro SparkDeposition SHS process Ti6Al4V

مهدي صالحي

عباس بهرامي

محمود منيرواقفي، بهروز موحدي، ابوذر طاهري زاده