ارزيابي خواص مكانيكي و ريز ساختاري كامپوزيت نانو ساختار Ti-SiC توليد شده به وسيله فرايند نورد پيوندي تجمعي

چكيده انگليسي :

Isfahan University of Technology Department of Materials Engineering Mechanical and Microstructural Evaluation of Nanostructured Ti SiC Composites Produced by Accumulative Roll Bonding Process Mohsen Karimi m karimi@ma iut ac ir December 15 2014 Department of Materials Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Mohammad Reza Toroghinejad Supervisor E mail toroghi@cc iut ac ir Khosro Farmanesh Advisor E mail khfarmanesh@mut es ac ir Depaertment Graduate Coordinator K Raeissi Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Department of Material Engineering Malek Ashtar University of Technology Isfahan Shahin shahr Iran Abstract In this study Accumulative roll bonding ARB was used as an alternative method for producing CP Ti SiC metal matrix composites The aim of this study was to evaluate the microstructural and mechanical properties of CP Ti SiC composites produced by ARB process For this purpose composites with 1 5 3 and of 5 vol of reinforcements and monolithic material were fabricated by ARB process Microstructural studies by means of light and electron microscopy and X ray diffraction pattern analysis texture measurements and also mechanical examination were done at various stages of the process The results showed that the addition of particles reduces the bond strength between layers because of the increased energy barrier required for bonding With increasing ARB cycles particles distribution was significantly improved with noticeable decrease in fracturing deboning of particles and porosities Microstructural parameters of heavily deformed materials have been characterized by X ray diffraction line profile analysis XRDLPA using modified Rietveld method The results indicated that the XRD technique can be used as a complementary method beside TEM to estimate the microstructural parameters Crystal size and anisotropy calculated by this method was in a good agreement with the observations of transmission electron microscopy and texture measurements Formation of nano size equiaxed grains in the final cycles was demonstrated by the two methods X ray diffraction and transmission electron microscopy A significant increase in yield and tensile strength and a drastic decrease in elongation were observed by applying 8 cycles of ARB process The strength of the composite samples was higher than that of the monolithic sample and this was caused by the significantly improved distribution of SiC particles in the titanium matrix The high strength and high toughness monolithic titanium and Ti SiCp composites were fabricated by accumulative roll bonding ARB and subsequent annealing To clarify the concurrent optimal processing conditions for strength and toughness optimizing multiple performance characteristics by Taguchi s approach was employed Yield strength of the processed specimen by optimal factor levels 1 5 vol SiC 500 C 5 minutes was 2 27 times higher and toughness was 5 8 lower than that of the raw titanium material High uniform elongation 17 of material produced in optimal conditions was attributed to the increased rate of work hardening and normalized work hardening rate in contrast with the initial Ti and related to very fine grained average grain size of 1 4 m and fully recrystallized structure and also reinforcment particles in ARB Annealed titanium Key words Commercially pure titanium Severe plastic deformation SPD Accumulative roll bonding ARB Metal matrix composites Mechanical properties Annealing Taguchi experimental design

كريمي، محسن

ارزيابي خواص مكانيكي و ريز ساختاري كامپوزيت نانو ساختار Ti-SiC توليد شده به وسيله فرايند نورد پيوندي تجمعي

تيتانيم خالص تجارتي ﴿CP Ti﴾ , كامپوزيت زمينه فلزي , فرايندهاي تغيير شكل شديد ﴿SPD﴾ , آنيل , طراحي آزمايش تاگوچي