نوع مقاله : مقاله کامل پژوهشی

نویسندگان

1 دانشکده مهندسی و علم مواد، دانشگاه صنعتی شیراز، شیراز، ایران

2 دانشکده مهندسی متالورژی و مواد، پردیس دانشکده های فنی، دانشگاه تهران، تهران، ایران

چکیده

در این تحقیق نانوکامپوزیت های Al-6061/Gr با زمینه نانوساختار و مقادیر مختلف میکروذرات گرافیت با روش متالورژی پودر (P/M) و با استفاده از آسیاکاری مکانیکی، پرس سرد و اکستروژن داغ تولید شدند. با توجه به محدودیت در مقدار نانوکامپوزیت های تولید شده و عدم امکان ساخت نمونه های استاندارد کشش، جهت بررسی خواص مکانیکی این مواد از آزمون سنبه برشی استفاده شد. نتایج XRD و SEM نشانگر توزیع یکنواخت ذرات گرافیت در زمینه نانوساختار آلومینیم بود. نتایج سختی سنجی نشان دادند که با افزایش درصد گرافیت سختی کاهش یافته است. نتایج آزمون سنبه برشی در دمای محیط نشان دادند که با ریز کردن ساختار دانه افزایش قابل توجهی در تنش تسلیم برشی و تنش برشی نهایی آلیاژ Al-6061 بدست می آید اما افزودن گرافیت موجب کاهش استحکام برشی و انعطاف پذیری نانوکامپوزیت Al/Gr می شود. استحکام بخشی هال-پچ را می توان به عنوان مکانیزم اصلی موثر بر استحکام بخشی برشی این کامپوزیت ها دانست.

کلیدواژه‌ها

عنوان مقاله [English]

Theoretical and Experimental Investigations on Shear Strength of Al 6061/Gr Nanocomposites Produced by Powder Metallurgy

نویسندگان [English]

  • Sareh Mosleh-Shirazi 1
  • Farshad Akhlaghi 2

1 Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz, Iran

2 School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran.

چکیده [English]

In the present study, Al 6061/Gr nanocomposites with a nanocrystalline matrix structure containing different amounts of graphite micro-particles were synthesized via Powder Metallurgy (P/M) method through mechanical milling, cold pressing and hot extrusion. Due to the limited quantity of the produced nano-composites and impossibility of making standard tensile test specimens, a shear punch test setup was used for evaluation of the mechanical properties of these materials. The results of XRD and SEM studies revealed that Gr particles were uniformly distributed in the nanostructured Al matrix. Hardness measurements showed that increasing the volume fraction of Gr resulted in decreased hardness of Al/Gr nanocomposites. The results of shear punch tests at room temperature revealed significant higher shear yield stress and ultimate shear strength by decreasing the grain size of Al-6061. However, Gr addition deteriorated the shear strength and ductility of Al/Gr nanocomposites. These observations confirmed that the Hall-petch mechanism was the major strengthening mechanism for these nanocomposites.

کلیدواژه‌ها [English]

  • Nanostructure
  • Powder Metallurgy
  • Nanocomposite
  • Shear strength
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