توسعه نانوکامپوزیت ریختگی درجای زمینه منیزیمی تقویت‌شده با نانوذرات اکسیدی با افزودن پودرفعال شده نانو سیلیکا به مذاب

نوع مقاله: مقاله پژوهشی

نویسندگان

1 بخش مهندسی مواد، پردیس دانشگاه صنعتی اصفهان،

2 دانشکده‌ مهندسی مواد، دانشگاه صنعتی اصفهان

3 استادیار پژوهشکده فولاد، دانشگاه صنعتی اصفهان

چکیده

در این پژوهش، نانوکامپوزیت‌های زمینه منیزیمی از جنس آلیاژ AZ91C تقویت‌شده با ذرات اکسیدی، به‌ صورت درجا با افزودن 2 درصد وزنی نانوسیلیکا به شکل مخلوط پودری 50wt.%Al+50wt.%SiO2(np) فعال‌سازی شده، به‌‌روش ریخته‌گری گردابی تهیه شد. ابتدا مخلوط پودری در شمش آلیاژ منیزیم جاگذاری شده و دمای آن تا °C800 افزایش یافت. سپس دمای مذاب به °C750 کاهش یافته و در این دما به‌ مدت 15 دقیقه هم‌زده شد. در نهایت، مخلوط مذاب و جامد کامپوزیتی در دمای °C720 در قالب فلزی پیش‌گرم شده ریخته‌گری شد. برای مقایسۀ‌ نتایج، نمونه‌های شاهدی نیز تحت شرایط کاملا یکسان ریختگی شدند. بررسی‌‌های ریزساختاری و مکانیکی، بهبود ریزساختار، کاهش تخلخل و افزایش سختی، استحکام کششی و استحکام تسلیم در نمونه‌های کامپوزیتی را نشان داد. مقدار سختی، استحکام تسلیم و استحکام کششی به‌‌ترتیب از 67 برینل، 84 مگاپاسکال و 168 مگاپاسکال در نمونه‌های بدون تقویت‌کننده به 80 برینل، 120 مگاپاسکال و 230 مگاپاسگال در نمونه‌های کامپوزیتی افزایش یافت. بر اساس بررسی‌های ریزساختاری و طیف‌سنجی پراش انرژی پرتو ایکس، به‌نظر می-رسد واکنش درجای آلومینیوم، منیزیم و سیلیکا باعث ایجاد ذرات تقویت‌کننده اکسیدی از جنس Al2O3 ، MgAl2O4 و MgO در زمینه شده است.

کلیدواژه‌ها


عنوان مقاله [English]

Development of in-situ cast magnesium matrix nano-composite reinforced with oxide nano particles by addition of activated nano-silica powder to the melt

نویسندگان [English]

  • Mansour Borouni 1
  • Behzad Niroumand 2
  • Ali Maleki 3
1 College of Pardis, Materials Engineering Section, Isfahan University of Technology
2 Professor, Department of Materials Engineering, Isfahan University of Technology
3 Assistant Professor, Research Institute for Steel, Isfahan University of Technology
چکیده [English]

In this study, AZ91C magnesium matrix in-situ nano-composites reinforced with oxide particles were produced by addition of 2 wt% nano silica in the form of a 50wt.%Al+50wt.%SiO2(np) activated powder mixture to the melt using stir casting method. For this purpose, the activated powder mixture was embedded in AZ91C ingots and their temperature was stabilized at 800°C. Then the melt temperature was reduced to 750°C and the composite slurry was stirred for 15 min. Finally the slurry was cast in a preheated die at 720°C. Control samples were also cast under the same conditions. Improved microstructure, reduced porosity and increased hardness, tensile strength and yield strength of the composite sample were revealed by microstructural and mechanical investigations. The hardness, yield strength and tensile strength values increased from 67 BHN, 84 MPa and 168 MPa for the monolithic samples to 80 MPa, 120 MPa and 230 MPa for the in-situ formed cast composites, respectively. Microstructural and EDS analyses suggested the in-situ formation of Al2O3, MgAl2O4 and MgO oxide particles by in-situ reaction of Al, Mg and SiO2 in the melt.

کلیدواژه‌ها [English]

  • AZ91C alloy
  • in-situ cast nano-composite
  • Silica Nanoparticles
  • Mechanical properties
  • stirs casting
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