6166

5763

كارشناسي ارشد

انتخاب و روش ساخت مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1390

دوازده،104ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

مرتضي شمعانيان، مهدي صالحي

29/5/90

حميدرضا سليمي جزي، بهنام لطفي

مهندسي مواد

ID5763

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Characterization of Co Ti C composite coatings Formed by GTAW Ali Izadi Email address a izadi@ma iut ac ir Date of Submission 2011 05 30 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 Mehdi Salehi ProfessorAbstractIn the carrent study the in situ fabrication process of a layered metal matrix composite coating was The coatingconsists of a matrix of cobalt titanium intermetallics and the reinforcement phase of titanium carbide Thefabrication process is welding was Gas Tungsten Arc Welding GTAW conducted using a pre placed powdermixture of elemental titanium cobalt and graphite Several materials characterization methods includingmicrostructure Vickers microhardness dilution phase formation wear fracture toughness were employed tostudy the coating and coating substrate interface The intermetallic phases in the matrix vary from Co richphases at the coating surface to Ti rich compounds near the substrate The interface is revealed to have a smoothprofile free of any porosity or cracks with good metallurgical bonding to the substrate The microstructures ofthese coating were studied by optical microscopy scanning electron microscopy SEM and X Ray Diffraction The specimens were investigated by energy dispersion spectroscopy EDS and micro hardness test was used Arelatively uniform hardness in the range of 760 980 HVN is achieved through a depth of 500m into the coating The surface hardness of specimen with 40 TiC was near 980 HVN and The hardness gradually decreases to400 HVN at the substrate interface The hardness evolution which is predictable using the Rule of Mixtures isexplained by the fraction of the carbide particles and the type of intermetallic compounds in the matrix Themechanism of wear was abrasive and adhesive wear The weight loss of specimen with increase in weightfraction of reinforcement decrease Mathematical models were developed to predict hardness and dilution percent of claddings Response surfacemethod RSM was used not only for development of the regression models but also for better understanding ofthe effect of variables In addition analysis of variance ANOVA was employed to check the adequacy of thedeveloped models Based on the results of the mathematical models it was observed that reinforcementparameters can significantly affect the hardness while they have not a significant effect on dilution percent Keywords Cladding Pulse current Composite of Ti Co TiC Fracture toughness Hardness Dilution ANOVA

مرتضي شمعانيان، مهدي صالحي

حميدرضا سليمي جزي، بهنام لطفي