بررسی مکانیزم واکنش، ساختار و خواص مکانیکی کامپوزیت درجای تولید شده در سیستم Al-V2O5

نوع مقاله : علمی و پژوهشی

نویسندگان

1 دانشگاه آزاد اسلامی واحد یزد

2 دانشگاه یزد

چکیده

در ‌این پژوهش، تولید درجای ماده ی مرکب به روش سنتز احتراقی آلومینوترمیک در مجموعه ی Al-V2O5 مطالعه شد. برای این منظور، مخلوط پودرهای آلومینیم و V2O5 با نسبت مولی 28 به 3 تحت آسیاکاری و تراکم سازی بعدی قرار گرفتند. برای بررسی دماهای وقوع تحوّلات فازی، از آزمون حرارتی افتراقی استفاده شد و با توجه به دمای پیک مربوط به واکنش‌ها‌، نمونه‌های خام عملیّات حرارتی شدند. ثابت شد که واکنش احیای V2O5 توسط آلومینیم، فرایندی گام‌به‌گام است که V2O4 و V2O3 به عنوان فازهای میانی اصلی و Al2O3-γ و Al23V4 به عنوان فازهای انتقالی، قبـل از تشکیل فازهای Al3V و Al2O3-α شکل می‌گیرند. بررسی‌های ریزساختاری و فازی نشان دادند که به دنبال تف‌جوشی تا دمای Cº 1000، فاز Al8V5 در فصل مشترک بین Al3V و Al2O3-α به دست می آید. افزون بر این، نتایج آزمون‌های سختی‌سنجی و فشار نشان دادند که سختی و استحکام نمونه‌ها با افزایش دمای گرمادهی، به دلیل تشکیل کسر حجمی ‌بالاتری از ترکیبات بین‌فلزی و سرامیکی، افزایش می یابند، امّا کرنش فشاری به دنبال شکل‌گیری بیش تر فاز ترد Al8V5، کاهش می‌یابد.

کلیدواژه‌ها

عنوان مقاله [English]

The Study of Reactions Mechanism, Microstructure and Mechanical Properties of In Situ Composite Produced In Al-V2O5 System

نویسندگان [English]

  • Mohammad Ashnagar 1
  • Alireza Mashreghi 2
  • Mehdi Kalantar 2
1 Mining and metallurgy, Yazd University, Yazd
2 Yazd University
چکیده [English]

In this research, fabrication of an in-situ composite via aluminothermic combustion synthesis in Al–V2O5 system has been investigated. For this purpose, the mixed powders of Al and V2O5 with molar ratio of 28 to 3 were ball milled and then compressed. Differential thermal analysis was used to evaluate the temperatures of phase transitions. Using the peak temperature of the reactions, the samples were subjected to heat treatment. It was shown that the reduction reaction of V2O5 by Al is a stepwise process and V2O4 and V2O3 as the main intermediate phases and γ-Al2O3 and Al23V4 as the transmission phases were formed before the formation of Al3V and α- Al2O3. Microstructural studies showed that after sintering at the temperatures up to 1000 ºC, Al8V5 phase is formed at the interface between the two phases of Al3V and α-Al2O3. Hardness and compression test results also showed that the hardness and strength of the samples increase with increasing heating temperature due to the formation of greater volume fraction of intermetallic compounds and ceramic phases, however, the compressive strain decreased because of the formation of a greater amount of the brittle phase Al8V5.

کلیدواژه‌ها [English]

  • in situ composite
  • Intermetallic compounds
  • aluminothermic
  • Differential thermal analysis

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