14144

12815

كارشناسي ارشد

انتخاب و شناسايي مواد

اصفهان : دانشگاه صنعتي اصفهان

1397

دوازده، ۱۳۵ص.: مصور، جدول، نقشه، نمودار

بهزاد نيرومند

احمد كرمانپور، رحمت الله عمادي

1397/09/18

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مواد

مهندسي مواد

ID12815

4 1 5 بررسیهای ریزساختاری 26 4 1 2 بررسیهای مکانیکی 46 4 1 4 تعیین چگالی نمونهها 96 4 6 ارائه خطای آزمایشها و پراکندگی یافتهها 16 فصل چهارم نتای و ب ث 66 9 5 مقدمه 66 9 2 اعتبار سنجی با استفاده از دادههای حرارتی 166 9 4 طراحی قالب مارپیچ 16 9 9 شبیهسازی ریختهگری مذاب آلیاژ زاماک 4 در قالب مارپیچ با ابعاد بهینهسازی شده 11 9 9 5 نتایج شبیهسازی 84 9 1 فراوری نیمهجامد آلیاژ زاماک 4 با استفاده از قالب مارپیچ 44 9 1 5 تعیین شرایط انجمادی آلیاژ زاماک 4 با استفاده از روش آنالیز حرارتی 44 9 1 2 مسیر انجمادی آلیاژ زاماک 4 665 9 1 4 تاثیر میزان فوق ذوب و دمای قالب بر ریزساختار 265 9 1 9 چگالی سنجی 255 9 1 1 مقایسه نتایج شبیهسازی با یافتههای آزمایشگاهی 255 9 1 6 خواص مکانیکی 655 9 6 فراوری نیمهجامد قلع خالص تجاری با استفاده از قالب مارپیچ 455 9 6 5 تعیین شرایط انجمادی قلع خالص تجاری با استفاده از آنالیز حرارتی 455 9 6 2 بررسیهای ریزساختاری 625 9 6 4 سختیسنجی نمونه ها 125 فصل پنجم نتیجهگیری و پیشنهادات 127 1 5 نتیجهگیری 825 1 2 پیشنهادات 645 مراجع 545 چکیده انگلیسی 145 هشت

Isfahan University of Technology Department of Materials Engineering Semi Solid Processing of Zamak 3 Alloy and Commercial Pure Tin using Serpentine Channel and its Structural and Mechanical Characterization Fasrhid Marani f marani@ma iut ac ir Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language PersianSupervisor Behzad Niroumand Prof E mail Behzn@cc iut ac irAbstractFormation of such defects as hot tear interdendritic porosity macro segregation and structuralanisotropy in dendritic solidification leads to undesirability of these structures as high sensitivitycomponents Consequently transformation of dendritic morphology of solidification structure ofengineering metals and alloys to a non dendrite one spherical or quasi spherical leads to morehomogeneous structural parts with higher mechanical properties This can be accomplished usingsemi solid casting processes On the other hand it is very difficult to process pure metals and closeto zero freezing range alloys in their semi solid state In the present study transformation ofdendritic morphology of Zamak 3 alloy and pure commercial tin was investigated using a modifiedserpentine channel method In order to optimize the dimensions of the serpentine channel whilemaintaining its special characteristics heat transfer and solidification of the alloy was simulatedusing ProCast software It was observed that the modified serpentine channel was capable ofintensifying the nucleation rate and maintaining the required self stirring conditions during thepassage of melt in the serpentine channel Melt temperature of 430 C and copper serpentinechannel temperature of 200 C were recognized as the optimum semi solid casting conditions forZamak 3 alloy Simulation results for this sample showed optimum surface and volume turbulenceswith the least solidification defects in this sample In these conditions the average shape factor ofthe primary solid particles was 0 85 and 10 increase in the strength and 40 increase in thetoughness compared to those of the control sample as well as the largest discharged slurry with agood fraction solid were observed In pure tin specimens the average shape factor of the primarysolid particles increased from 0 69 to 0 85 by increasing the temperature from 270 C to 370 C but the hardness decreased by 15 due to the structural coarsening Suitable pouring temperaturefor producing the optimal pure tin sample was found to be 320 C Copious nucleation of theprimary particles in the serpentine channel reduction of the thermal and solutal gradient ahead ofthe growing solid particles as well as self stirring of the semi solid slurry and self rotation of thesolid particles were recognized as the main mechanism for dendritic to non dendritictransformation of the microstructures Keywords Semi solid casting Serpentine channel Non dendritic microstructure Mechanical properties Zamak 3 Pure Tin Simulation

بهزاد نيرومند

احمد كرمانپور، رحمت الله عمادي