10107

9337

كارشناسي ارشد

شناسايي و انتخاب و روش ساخت مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1393

سيزده، 81ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

محمدرضا طرقي نژاد، احمد رضاييان

قاسم ديني تركماني

3/3/94

حسين ادريس، محمود منير واقفي

1396/10/02

كتابنامه

مواد

مهندسي مواد

ID9337

4 3 آمادهساز نمونهها قبل از نورد نهايي نورد سرد اوليه آنيل مياني 53 4 4 ريزساختار نمونهها پس از نورد نهايي 73 4 5 ريزساختار نمونهها پس از آنيل نهايي 93 4 6 تعيين كسر تبلورمجدد 74 4 7 تعيين دانسيته نابجاييها 84 4 8 ارزيابي خواص مكانيكي 15 4 8 1 تغييرات سختي 15 4 8 2 نتايج آزمون كشش 25 4 9 آنيل در كوره حمام نمك 85 4 9 1 بررسيها ريزساختار نمونهها آنيل شده در محدوده دما بازيابي 85 4 9 2 بررسيها ريزساختار نمونهها آنيل شده در محدوده دما تبلورمجدد 06 4 9 3 تاثير بازيابي و تبلورمجدد بر ريزساختار 27 4 01 محاسبه دانسيته نابجاييها 67 4 11 ارزيابي خواص مكانيكي 76 تغييرات سختي نمونهها 76 4 11 1 4 11 2 نتايج آزمون كشش 86 4 21 جمعبند كلي 37 فصل پنجم نتيجهگير و پيشنهادات 57 68 5 1 نتيجهگير 5 2 پيشنهادات 78 مراجع 87 چكيده انگليسي 28 نه

92 The influence of thermo mechanical processing on microstructure and the mechanical properties of the Cu 35Zn brass Mahsa Beheshti Fard m beheshtifard@ma iut ac ir Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Mohammad Reza Toroghinezhad toroghi@cc iut ac irAhmad Rezaeian a rezaeian@cc iut ac irAbstractIn this work microstructural and mechanical properties of a cold rolled and annealed Cu 35Zn wereinvestigated through the control of recovery and recrystallization kinetics The main objective ofthis research was optimization of thermomechanical condition to achieve the maximum toughnessby taking advantage of the bimodal microstructure as well as partial recrystallization concepts Forthis purpose two approaches were considered In the first the annealed brass samples were coldrolled to reductions of 60 75 and 90 and were subsequently annealed in electrical furnace attemperatures from 300 C to 550 C Results revealed that in the partial recrystallization temperaturerange high strength due to non recrystallized portion whereas in the full recrystallizationtemperature range high ductility due to recrystallized portion were achieved In the secondapproach the 90 cold rolled samples were annealed in a salt bath furnace for 10 minutes Due tohigher heat transformation in the salt bath as compared to the electrical furnace differentmechanical properties were achieved Selected samples were annealed in recovery andrecrystallization temperatures 250 C and 450 C respectively In order to investigate thecompetition between the above processes samples were annealed at both temperatures for variousholding times The tensile test indicated that the ductility of samples that annealed in recoverytemperature range were improved mainly due to decreasing of dislocation density in the presenceof mechanical twins Also strength and ductility were improved for samples annealed inrecrystallization temperature range for 1 and 5 minutes because of partial recrystallization and forthe samples annealed for 10 minutes due to the bimodal grain size distribution On the other hand in samples annealed in both the recovery and recrystallization temperature range the recoveryconsumed low proportion of stored energy and by increasing the proportion of recovery thanrecrystallization ultimate tensile strength and yield stress were increased due to the partialrecrystallization while the ductility was decreased Comparison of the results in the twoapproaches indicated that the toughness of the samples processed in the salt bath furnace was about220MJ m to 245MJ m while for the ones annealed in the electrical furnace the maximum of 3 3toughness was 220MJ m 3Keywords Cu 35Zn brass Cold rolling Recovery and recrystallization Microstructure Strength and ductility

محمدرضا طرقي نژاد، احمد رضاييان

قاسم ديني تركماني

حسين ادريس، محمود منير واقفي