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Development and Characterization of Iron-Cobalt Feco Based Bulk Metallic Glass Bmg Materials

Thesis Info

Access Option

External Link

Author

Syed Zameer Abbas

Program

PhD

Institute

Ghulam Ishaq Khan Institute of Engineering Sciences and Technology

City

Topi

Province

KPK

Country

Pakistan

Thesis Completing Year

2016

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/8186/1/S%20Zameer%20Abbas_Mat%20Sci%20%26%20Engg_2017_GIKI_HSR-14-12-17.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725853881

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Bulk metallic glass (BMG) is an important class of materials possessing unique set of properties. Iron Cobalt (FeCo) based BMGs have properties especially suited for applications where high strength and wear resistance is required like surgical tools and mechanical precision elements. These can also be used in electromechanical conversion devices. The current thesis is aimed at the study of the mechanical properties of the FeCo based BMGs. Three FeCo-based BMGs with the compositions (Fe0.5Co0.5)69-xNb6B25+x (x = 0, 2, 4) were cast using electric arc melting and suction casting technique. For each composition three samples were prepared, tested, and analysed in as-cast, annealed and partially crystalline conditions. The as-cast alloys possessed high hardness that was found to increase with annealing and partial crystallization. Hardness values approaching 1400 HV were obtained for partially crystalline BMG alloy having the maximum boron content. In X-ray diffraction scans no peaks that indicate crystallinity in the BMG alloys were observed in the as-cast and annealed condition while small broad peaks were present in the diffraction patterns of partially crystalline alloy samples. Glass transition (Tg) and crystallization (Tx) temperatures of all the three BMG alloys in as-cast condition were above 800 K. Saturation magnetization (MS) has shown a decrease while magnetic coercivity (HC) increased with an increase in boron content of the alloy. The maximum value of MS (92 emu/g) was obtained for annealed BMG alloy with the maximum iron-cobalt content. Indentation of the BMG alloys resulted in the formation of the deformation zone underneath the indents that consisted of shear bands. Annealing of the cast FeCo based BMG alloys resulted in a decrease in the size of the deformation zone as compared to as-cast amorphous alloys mainly because of increase in strength of the alloys. Plastically deformed zone size calculations through available models show an overestimation of the zone size. Indentation of partially crystalline alloys (intrinsic composites) produced corner cracks while no cracks were observed in case of as-cast and annealed alloys. Palmqvist crack morphology was observed for corner cracks at all the indentation loads used. Indentation fracture toughness of intrinsic composites was obtained by calculations based on the measured corner crack lengths. Indentation fracture toughness values ranging in 1.85 MPa√m to 2.9 MPa√m, were obtained. Best mechanical properties and thermal stability was shown by the alloy with the highest boron content (29 at%) while better magnetic properties were exhibited by the other two BMG alloys.
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کہتے ہیں اس جہاں کے یہ قصے حقیر ہیں

کہتے ہیں اس جہاں کے یہ قصے حقیر ہیں
جاناں تمھارے خواب بھی کتنے شریر ہیں

ہم آسمانِ زیست کے تابندہ لوگ تھے
ہم تیرے در پہ آ کے بنے جو فقیر ہیں

مصرع کمر ہے، شعر سی تصویر ہے تری
تجھ خوبرو کو دیکھنے آئے جو میرؔ ہیں

تیری رضا پہ ہے سرِ تسلیم خم مرا
تجھ زلف کے اے شوخ پرانے اسیر ہیں

گل ہو، گہر ہو، لعل ہو یا پورا چاند ہو
جاناں تمھارے حسن کے آگے حقیر ہیں

بزمِ فضاؔ میں ناز کا کیا کام گل بدن
یاں آئے بادشاہ بھی بن کر فقیر ہیں

Perkawinan Beda Agama di Republik Yaman Perspektif Hukum Islam dan Hukum Positif

Writing this article wants to describe, related to Yemeni legal regulations, namely the marriage of Muslim women in Yemen. Discussing the annulment of marriages for men who adhere to Islam or Muslims who do not marry Muslim women and women of the book in Yemen. As for the women of the People of the Book who can be married to Muslim men in Yemen, it is necessary to elaborate on the permissibility of marrying women who are not Muslim. Yemen itself fully takes the source of law in the text of the Koran where marriage regulations in Yemen between Muslim men and women of the book are permissible and regulated in Yemen's legal laws. On the other hand, interfaith marriages in other regions related to women of the book cannot be found, in Indonesia, for example, interfaith marriages only describe marriages between Muslims and those who are not Muslim or are not Muslim, there is absolutely no mention of women of the book. For this reason, this article wants to elaborate on the explanation regarding women of the People of the Book, amidst the debate whether or not it is permissible to marry women of the People of the Book, Yemen still adheres to the Al-Quran text which allows Muslim men to marry women of the People of the Book until now.

Enhanced Production of Butyric Acid Through Solid State Fermentation of Agriculture Waste by Mutant Clostridium Tyrobutyricum and its Utilization in Early Rumen Development

Due to lessening availability of crude oil, increasing requirement for natural foodstuffs, increasing worries over environment and one of alternative fuel, production of butyric acid through bacterial activity is greatly increased. The present study was designed to improve its production through solid state fermentation technology by microbe using cheaper renewable biomass. For this purpose three agriculture wastes as carbon source were tested for optimum yield applying solid state fermentation technique by wild C.tyrobutyricum. Rice polishings with 2 mL inoculum volume of the growth medium at 37oC, pH 6.0 for 3 days incubation period and 10:32 substrate: water ratio gave the best yield (6.49mg) among them and was selected for further optimization procedure to get higher yield of butyric acid. Various concentrations of different ionic salts such as NaCl, CaCl2, MgSO4.7H2O and KH2PO4.2H2O were optimized and obtained 6.52, 6.89, 8.15 and 8.95 mg butyric acid respectively. The addition of optimized 1:20 nitrogen: carbon ratio of molasses and optimized 0.5 mL concentration of corn steep liquor as an additive gave significantly (P< 0.05) highest yield i.e.11.07 and 18.23 mg butyric acid respectively. To further enhance the yield of butyric acid, bacterial strain was upgraded. For this purpose two chemical mutagens ethidium bromide, nitrous acid and physical mutagen UV irradiation were utilized. The RCM plates containing more than 90% kill rate were selected and mutants were screened on RCM media for optimized yield of butyric acid against wild C.tyrobutyricum. The UV mutant gave the better yield of butyric acid 4.46 mg than wild and other two mutants (nitrous acid and ethidium treated). The optimized three day incubation period gave butyric acid yield (6.86 mg %) which was further increased at10:32 substrate: water ratio (7.47 mg) and by optimizing inoculum volume, better yield (7.69 mg) of butyric acid was achieved with 2.5 mL inoculum volume. Different ionic salts such as NaCl, CaCl2, MgSO4.7H2O and KH2PO4.2H2O raised butyric acid yield 8.8 and 9.6, 10.52, 10.66 mg respectively. The addition of optimized 1:25 nitrogen: carbon ratio and under optimized 0.6 mL concentration of corn steep liquor of the growth medium as an additive gave significantly (P<0.00)the highest yield 11.63 and 26.09 mg ofbutyric acid respectively. The mutant strain C.T UV showed more butyric acid capability compared to wild C.tyrobutyricum. Detection and estimation of butyric acid was carried out by organic analysis method by G. Deniges (1918). The parameters optimized on small scale by mutant C.T UV were then used on laboratory scale for butyric acid production and was biologically evaluated. It was carried out by conducting 90 days feeding trials on sixteen Lohi sheep kids of age between 25-35 days, almost uniform weight and mixed sex. The animals were randomly grouped into A, B, C, and D containing four sheep each. D group of sheep was served as control group and was fed on control diet. Whereas A, B, C were supplemented with 0.2, 0.4, 0.6 % (w/w) butyric acid along with the same rations fed to control group. All animals were weighed initially and thereafter weighed weekly. While blood sampling for estimation of butyric acid, complete blood count and glucose were done initially and thereafter fortnightly. To visualize the inner surface of walls and papillae development in the rumen the Pentax EPK-100 P endoscope was used for sheep. One fasted sheep from each group was randomly selected for this purpose as well as for slaughtering at the end of feeding trial. From different portions of rumen i.e. dorsal, ventral, caudal dorsal, caudal ventral, dorsal cranial and from ventral cranial sacs of each slaughtered animal samples were taken for histological examination. Slides were observed under light microscope (Labomed USA) for measuring the papilla length, height, width, denseness and surface area of papilla by using the Morphometric program pro ResR 2.1.1 Capture Prog Camera Control software. The results showed non-significant (P > 0.05) increase in CBC and in blood glucose levels in experimental animals as well in control groups. Whereas significant (P<0.05) difference was seen in butyric acid levels in serum among treatments and control. Group C showed significantly higher concentration of butyric acid in serum than others. Among all groups Non significant (P >0.05) effect on body weights was noted. However a significance difference in the papillae length, width, rumen sacs surface areas and denseness was noted, when histological examination of rumen sacs was performed. It is concluded that solid state fermentation technique can be applied on industrial scale to produce massive quantity of butyric acid by mutated strain of C.tyrobutyricum. Butyric acid augmented in the diet improved the rumen growth in sheep.