نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد، دانشکده مهندسی مواد، دانشگاه علم وصنعت ایران، تهران، ایران

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

3 دانشیار، دانشکده مهندسی مواد. دانشگاه علم و صنعت ایران، تهران، ایران

چکیده

چکیده
ریخته‌گری گریز از مرکز یکی از روش‌هایی است که برای تولید کامپوزیت‌های دوفلزی و به دو روش، افقی و عمودی، به‌کار گرفته می‌شود. حالت عمودی این روش، که در این تحقیق به‌کار گرفته شد، برای تولید قطعاتی متداول است که نسبت ارتفاع به قطرشان کم‌تر از واحد باشد. در این تحقیق، مذاب آلومینیم با نسبت‌های مذاب به جامد 5/1 و 5/2 درون بوش برنجی پیش‌گرم شده تا دمای 100 درجه‌ی سلسیوس و در حال چرخش با سرعت‌های دوران 800، 1600 و 2000 دور بر دقیقه ریخته‌گری شد. از میکروسکوپ نوری (OM) و میکروسکوپ الکترنی روبشی (SEM) برای مشاهدات میکروسکوپی و نیز از طیف‌سنج پراش پرتو ایکس (EDS) برای شناسایی فازهای تشکیل شده، استفاده شد. به نظر می‌رسد که جریان یافتن مذاب در حوزه‌ی گریز از مرکز با گسیختن فیلم اکسیدی سطحی مذاب آلومینیم همراه است به‌گونه‌ای که شرایط برای تشکیل پیوند متالورژیکی مساعد می‌شود. از طرف دیگر، پاره شدن این فیلم اکسیدی سطحی به‌همراه تلاطم ذاتی فرآیند ممکن است موجب بروز عیوبی در قطعه ‌شود. نتایج این تحقیق نشان داد کامپوزیت‌های تولید شده به ازای دور 2000 بیش‌تر از سایر قطعات در معرض عیوب هستند. این مقاله عیوب مختلف مشاهده شده را دسته‌بندی کرده و اثر متغیرهای مختلف موثر را بررسی می‌کند.

کلیدواژه‌ها

عنوان مقاله [English]

Defects characterization of Al-brass composite produced via centrifugal process

نویسندگان [English]

  • Morteza Gholami 1
  • Mehdi Divandari 2
  • Mohammad Taghi Salehi 3

1 Department of Material Engineering, Iran University of Science and Technology, Tehran, Iran

2 Department of Material Engineering, Iran University of Science and Technology, Tehran, Iran

3 Department of Material Engineering, Iran University of Science and Technology, Tehran, Iran

چکیده [English]

Centrifugal casting is one of the methods which is used for producing bimetallic composite parts. This method runs both horizontal and vertical mode. Vertical mode, used in this work, is currently taken to produce casting parts with height to diameter ratio less than unity. In this study, aluminum melt with 1.5 and 2.5 melt-to-solid volume ratio was cast into 100°C preheated  brass bush rotating at 800, 1600, and 2000 (rpm), respectively. In order to characterize the cast samples, possible phases and casting defects various equipment such as optical microscope (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) have been used. Flowing of Al melt, at centrifugal field, is possibly associated with surface oxide film rupture so that metallurgical bonding is attained. On the other hand, these oxide films flowing at the melt surface and inherent turbulence of this process may cause defects in the casting. It was noted that bimetal composites produced at 2000 rpm are subjected to more defects than the other. This article categorizes various defects seen and analyzes different effective parameters.

کلیدواژه‌ها [English]

  • Aluminum-brass composite
  • centrifuge casting
  • defects
  • surface oxide film

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