اثر نورد سرد و آنیل کوتاه مدت روی ریزساختار و سختی آلیاژ آلومینیم A356

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی مواد، دانشگاه صنعتی نوشیروانی بابل، بابل، ایران

چکیده

در این پژوهش، اثر نورد سرد و عملیات حرارتی کوتاه‌مدت روی ریزساختار و سختی آلیاژ آلومینیم 356A بررسی شد. مشاهدات ریزساختاری توسط میکروسکوپ نوری، آنالیز کمّی با استفاده از نرم‌افزار کلمکس و آزمون سختی‌سنجی توسط سختی‌سنج برینل انجام شد. نتایج نشان داد که فرایند نورد باعث ریز شدن، افزایش کرویت و کاهش نسبت طول به عرض ذرات سیلیسیم و نیز حذف تخلخل‌های موجود در نمونه‌ی ریختگی شد. توزیع ذرات سیلیسیم در مقطع RD-ND نسبت به مقطع RD-TD یکنواخت‌تر بود زیرا در فرایند نورد ورق تغییرات ابعادی فقط در جهات RD و ND رخ می‌دهد و در نتیجه تغییرشکل پلاستیک بیش‌تری در مقطع RD-ND به وجود آمده و توزیع ذرات سیلیسیم که کاملا وابسته به مقدار تغییرشکل پلاستیک است در این مقطع یکنواخت‌تر شد. همچنین، نورد و عملیات حرارتی موجب ریزشدن دانه‌های آلومینیم از طریق فعالسازی مکانیزم‌های تبلورمجدد پیوسته و جوانه‌زنی تحریک شده توسط ذرات شد. ذرات سیلیسیم علاوه بر این که موجب تولید دانه‌های ریزتری شدند، از رشد این دانه‌ها نیز جلوگیری کردند. فرایند نورد موجب افزایش سختی نمونه شد اما انجام عملیت حرارتی تا 300 ثانیه، سختی را کاهش داد. در نهایت، افزایش زمان عملیات حرارتی به 600 ثانیه به دلیل کامل شدن مکانیزم تبلورمجدد پیوسته موجب افزایش سختی به میزان 26% گردید.

کلیدواژه‌ها


عنوان مقاله [English]

Effect of cold rolling and short-term annealing on microstructure and hardness of A356 aluminum alloy

نویسندگان [English]

  • Mohammad Amin Jafari Jozan
  • Roohollah Jamaati
Department of Materials Engineering, Babol Noshirvani University of Technology, Babol, Iran
چکیده [English]

In this research, the effect of cold rolling and short-term heat treatment on the microstructure and hardness of A356 aluminum alloy were investigated. Microstructural observations by optical microscopy, quantitative analysis using Clemex software and hardness test by Brinell macrohardness were performed. The results showed that the rolling process led to refining, increasing the sphericity, and decreasing the aspect ratio of the silicon particles, as well as removal of porosity in the casting sample. The distribution of silicon particles at the RD-ND plane was more uniform than the RD-TD and section because during the rolling process, the dimensional changes occurs only in the RD and ND directions, resulting in more plastic deformation at the RD-ND plane, and the distribution of silicon particles which is totally dependent on the amount of plastic deformation became more uniform. Also, rolling and heat treatment caused the grain refinement of aluminum through activation of continuous recrystallization and particle stimulated nucleation (PSN) mechanisms. The presence of silicon particles resulted in formation of finer grains and also suppression of the grain growth. Rolling process increased the hardness of the sample, but the heat treatment up to 300 s reduced the hardness. Finally, increasing the heat treatment time to 600 s resulted in an increase in hardness of 26% due to the completion of the continuous recrystallization mechanism.

کلیدواژه‌ها [English]

  • Aluminum alloy
  • Rolling
  • Annealing
  • Microstructure
  • Hardness
[1]       S. Amirkhanlou, M. R. Rezaei, B. Niroumand, M. R. Toroghinejad, High strength and highly-uniform composites produced by compocasting and cold rolling processes, Materials and Design, Vol. 32, No. 4, pp. 2085–2090, 2011.
[2]       R. Jamaati, S. Amirkhanlou, M.R. Toroghinejad, B. Niroumand, CAR process: A technique for significant enhancement of as-cast MMC properties, Materials Characterization, Vol. 62, No. 12, pp. 1228–1234, 2011.
[3]       S. Amirkhanlou, R. Jamaati, B. Niroumand, M. R. Toroghinejad, Using ARB process as a solution for dilemma of Si and SiCp distribution in cast Al–Si/SiCp composites, Journal of Materials Processing Technology, Vol. 211, No. 6, pp. 1159–1165, 2011.
[4]       R. Jamaati, S. Amirkhanlou, M. R. Toroghinejad, B. Niroumand, Comparison of the microstructure and mechanical properties of as-cast A356/SiC MMC processed by ARB and CAR methods, Journal of Materials Engineering and Performance, Vol. 21, No. 7, pp. 1249–1253, 2011.
[5]       P. Davami, M. Ostad Shabani, R. Rahimipour, A. Tofigh, Influence of time and temperature solutionizing on spheroidization of the silicon particles of AMNCs, Tehran, Iran, june, pp. 12-28, 2016.
[6]       S. Mousavi, S. Shabestari, Investigation of the effect of heat treatment of hardening on microstructure and impact resistance of A356 alloy, Shiraz, Iran, November 8-9, 2016.
[7]       P. Momeni, R. Jamaati, Effect of accumulative roll bonding process on microstructure and hardness of A356/TiC cast composite, Modares Mechanical Engineering, Vol. 17, No. 9, pp. 390-396, 2017.
[8]       E. Damavandi, S. Nourouzi, S.M. Rabiee, Effect of porosity on microstructure and mechanical properties of Al2O3(p)/Al-A356 MMC, Modares Mechanical Engineering, Vol. 15, No. 3, pp. 243-250, 2014.
[9]       M. Amnelahi, S. Shabestari, Effect of Thermal Treatment of Germination, Improvement and Thermal Treatment on the Microstructure and Strength of Aluminum Alloy 356, The sixth congress of material engineering, Iran, November 6-8, 2012.
[10]    N. Iri, A. Abedi, The effect of different T6 heat treatment conditions on the microstructure and hardness of A356/SiC nanocomposites, Shahroud, Iran, February 29-30, 2012.
[11]    V. Tari, M. Kianinia, E. Dahkordi, Investigation of the effect of thermal re-aging treatment on the mechanical properties of aluminum alloy T6-7075, The eleventh of congress material engineering, Iran, November 25-26, 2014.
[12]   A. Heydari, V. Shakeri, M. Golestanipour, Effect of thermal treatment on the compressive strength of aluminum foam A356, The first national congress of metal and non-monetary alloys, 17, Oct, 2017.
[13]    M. Naseri, R. Jamaati, M.R. Torghinejad Abrasion behavior of aluminum/alumina composite produced by cumulative rolling process, The fifth congress of materials engineering and casting society of Iran, October 3-4, 2011.
[14]    H. Mahjou, M. Nezafati, Correction of the structure and mechanical properties of aluminum 7075-T6 by thermal aging, Third national conference of heat treatment, May 10-11, 2012.
[15]    K. Amouri, J. Amouri, S. Ahmadifard, M. Kazazi, S. Kazemi, Preparation and characterization of A356 composite reinforced with SiC nano and microparticles by stir casting method, Modares Mechanical Engineering, Vol. 16, No. 10, pp. 335-342, 2014.
[16]    A. Eshaghi, H. R. Ghasemi, R, Taghiabadi, The effect of T6 heat treatment on the microstructure of aluminum-silicon 322, The eleventh congress of material engineering, Iran, November 25-26, 2014.
[17]    S.M. Hosseini, S.J. Hosseinipour, A. Gorji, S. Nourouzi, F. Zhalefar, Prediction of the behavior of the ductility and mechanical properties of aluminum alloy AA6063 after heat treatment, The fourth congress of material engineering, Iran, November 5-6, 2010.
[18]    B. Shahriari, F. Akhlaghi, Optimization of the heat treatment process to create a cellular structure in the aluminum alloy A356, The seventh national seminar of surfacing engineering and heat treatment, Iran, October 16-17, 2006.
[19]    M.A. Saboohi, S. Hoseinnejad, Investigating of the cold rolling and annealing effects on microstructure and mechanical properties of nanostructured Ni-Cr-Mn Marajing steel, Metallurgical Enginnering, Vol. 54, No. 1, pp. 24-29, 2014.
[20]       P. Asghari-Rad, M. Nili-Ahmadabadi, H. Shirazi, Semi-Solid Microstructural Evolution of Severely Deformed AISI 304 Stainless Steel. Metallurgical Engineering, Vol. 19, No. 2, pp. 94-108, 2016.
[21]       M.H. Shaeri, M. Shaeri, M.T. Salehi, S.H. Seyyedein, M.R. Abutalebi, Texture evolution of ultrafine grained Al-7075 alloy produced by ECAP, Metallurgical Enginnering, Vol. 56, No. 2, pp. 49-57, 2015.
[22]       A. Sedghi, M.H. Shaeri, L. Shahrdami, Microstructural and mechanical characterization of Al/CNT-SiCW hybrid nanocomposite prepared by hot pressing. Metallurgical Engineering, Vol. 20, No. 1, pp. 26-36, 2017.
[23]       M.F. Tarazkouhi, H.R. Jafarian, M.R. Aboutalebi, A. Ghorbanian, H. Shirazi, Microstructure evolution and mechanical properties during cold rolling and reverse transformation in Fe-18 Ni Martensitic Steel. Metallurgical Engineering, Vol. 20, No. 3, pp. 162-171, 2017.
[24]       S. Etemadi Maleki, E. Etemadi, S.G. Shabestari, F. Rikhtegar, Investigation on hardness and porosity of Al-CNT and Al2024-CNT nanocomposites produced by cold press-sintering and spark plasma sintering (SPS) methods, Metallurgical Engineering, Vol. 20, No. 3, pp. 209-218, 2017.