نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکترا، مهندسی مواد، دانشگاه علم و صنعت ایران، تهران، ایران

2 دانشیار، مهندسی مواد، دانشگاه علم و صنعت ایران، تهران، ایران

3 استاد، دانشکده مهندسی مواد، دانشگاه علم و صنعت ایران، تهران، ایران

چکیده

در این پژوهش از فرآیند پرس در قالب زاویه­دار (ECAP) برای ساخت کامپوزیت حجیم زمینه آلومینیمی با تقویت‌کننده‌ی ذرات آمورف Al65Cu20Ti15 استفاده شد. هدف از این پژوهش، بررسی نقش مکانیزم‌های استحکام‌دهی مختلف در تعیین استحکام نمونه‌های متراکم‌سازی شده است. به‌همین منظور، کامپوزیت حاوی 13 درصد وزنی از ذرات تقویت‌کننده آمورف تولید و رفتار مکانیکی آن با آلومینیم خالص متراکم­سازی شده در شرایط یکسان مقایسه شد. ارزیابی نقش مکانیزم‌های استحکام‌دهی در خواص مکانیکی نمونه‌ها مستلزم مشاهده و تحلیل دقیق مشخصه­های ریزساختاری و تحولات فازی رخ داده است. بنابراین، تحولات ریزساختاری توسط میکروسکوپ الکترونی روبشی نشر میدانی (FE-SEM) و آنالیز پراش پرتو ایکس (XRD) بررسی شد. همچنین، چگالی نابجایی‌های ذخیره شده در نمونه‌های مختلف با استفاده از الگوهای پراش پرتو ایکس و بهره‌گیری از روابط موجود محاسبه شد. از نرم‌افزار Clemex و روش‌های آماری برای کمی سازی مشخصات ریزساختاری بهره گرفته شد. چگالی نمونه‌های متراکمسازی شده توسط روش ارشمیدس اندازه‌گیری شد. ارزیابی خواص مکانیکی نمونه­های متراکم‌سازی شده توسط آزمون فشار تک‌محوری انجام گرفت. با بررسی‌های ریزساختاری و تعیین مشخصه­های ریزساختار اعم از اندازه دانه و چگالی نابه‌جایی­های ذخیره شده، می‌توان کرنش سختی را به‌عنوان مکانیزم استحکام‌دهی اصلی در افزایش استحکام نمونه‌های متراکم‌سازی شده معرفی نمود. از طرفی، حضور عیوب ریزساختاری، سبب انحراف مقدار استحکام اندازه‌گیری شده توسط آزمون فشار تک محوری و مقدار پیش بینی شده توسط مکانیزم‌های استحکام‌دهی شد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Study of strengthening mechanisms in an Al-Cu-Ti metallic glass reinforced Al matrix composite consolidated by ECAP process

نویسندگان [English]

  • Mohammad Reza Rezaei 1
  • Seyed Hossein Razavi 2
  • Saeed Shabestari 3

1 Center of Excellence for High Strength Alloys technology (CEHSAT), School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran

2 Center of Excellence for High Strength Alloys technology (CEHSAT), School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran

3 Center of Excellence for High Strength Alloys technology (CEHSAT), School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran

چکیده [English]

In this study, equal channel angular pressing (ECAP) process was used to consolidate an Al-Cu-Ti metallic glass reinforced aluminum matrix composite. The role of strengthening mechanisms in the strength of developed composite was investigated. The composite with 13 wt% of amorphous reinforcements was produced and the mechanical properties were compared with pure Al specimen which consolidated in the same conditions. Precise study of microstructural features as well as phase transformations is necessary for evaluating the role of strengthening mechanisms on mechanical properties of consolidated specimens. Hence, microstructural evolutions were examined using field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) method. Also, dislocations density was calculated through equations based on the characteristics of crystalline peaks in XRD patterns. Clemex software was also used to quantify the constituents of microstructures. The densities of the consolidated samples were measured by Archimedes method. Uniaxial compression test was utilized to determine the mechanical properties. Microstructural studies and assessment of microstructural features such as grain size and stored dislocations density revealed that strain hardening mechanism play the major role in the strengthening of consolidated specimens. On the other hand, presence of microstructural defects led to some discrepancies between measured and anticipated strength.

کلیدواژه‌ها [English]

  • Equal channel angular
  • pressing (ECAP)
  • Aluminum matrix composite
  • amorphous Al65Cu20Ti15
  • Strengthening mechanisms

 

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