تأثیر دما و نرخ کرنش بر رفتار تغییر شکل مومسان شیشه‌فلز حجمی آلیاژ Zr46(Cu4.5/5.5Ag1/5.5)46Al8

نویسنده

دانشکده فنی و مهندسی، بخش مهندسی مواد و متالورژی، دانشگاه شهید باهنر کرمان، کرمان، ایران

چکیده

در این تحقیق اثر دما و نرخ کرنش بر رفتار جریان مومسان شیشه‌فلز حجمی آلیاژ پایه زیرکونیم در حین آزمون خمش سه‌نقطه‌ای بررسی و ارتباط بین حساسیت به نرخ کرنش (m) و نوع جریان مطالعه شده است. بررسی منحنی‌های تنش- کرنش خمشی، نشان‌دهنده دو نوع جریان مضرّس و غیرمضرّس وابسته به دما و نرخ کرنش است. در دماهای بالای یک دمای بحرانی و یا نرخ‌های کرنش کمتر از یک حد بحرانی، جریان مضرّس پدیدار می‌شود که ناشی از فعال شدن همزمان نواحی استحاله برشی (STZ) و فرایندهای آسایش ساختاری وابسته به زمان است. همچنین در دماهای بالاتر از 0/4 دمای انتقالی شیشه، m منفی و در زیر آن دما، m مثبت خواهد بود. دلیل منفی بودن m ، نبودن زمان کافی برای فعال شدن فرایندهای آسایش ساختاری در نرخ‌های کرنش بالا است که باعث افزایش حجم آزاد در نوارهای برشی و درنتیجه نرم شدن ماده می‌شود. مقایسه انرژی فعال‌سازی نواحی استحاله برشی و انرژی لازم برای شروع جریان مضرّس نشان می‌دهد که این دو انرژی تقریباً با هم برابر بوده و ارتباط نزدیکی بین پدیده جریان مضرّس و عملکرد نواحی استحاله برشی وجود دارد.

کلیدواژه‌ها


عنوان مقاله [English]

Effect of Temperature and Strain Rate on Plastic Deformation Behavior of Zr46(Cu4.5/5.5Ag1/5.5)46Al8 Bulk Metallic Glass

نویسنده [English]

  • M. T. Asadi Khanouki
Department of Materials Engineering and Metallurgy, Shahid Bahonar University of Kerman, Kerman, Iran
چکیده [English]

In this study, the influence of temperature and strain rate on plastic flow of a Zr-based bulk metallic glass (BMG) during the three-point bending test was studied to find a correlation between strain rate sensitivity (m) and flow behavior. The flexural stress-deflection curves revealed two distinct types of dynamics, serrated and non-serrated flow, related to temperature and strain rate. The serrated flow which appeared at temperatures higher than a critical value or strain rates lower than a critical value, was simultaneously due to activation of shear transformation zones (STZs) and time-dependent structural relaxations. Further results indicated negative and positive values of m at temperatures above and below 0.4 Tg, respectively. The main reason for negative strain rate sensitivity was insufficient time of structural relaxation at high strain rates which lead to generation of free volume inside shear bands making the BMG softer. Comparison of STZ activation energy with activation energy for the onset of serration indicated almost equal values and there was a close relationship between serrated flow and STZ operation.

کلیدواژه‌ها [English]

  • Bulk metallic glass
  • Strain rate sensitivity
  • Shear transformation zone
  • Serrated flow
  • Structural relaxation
1. Trexler, M. M., and Thadhani, N. N., “Mechanical Properties of Bulk Metallic Glasses”, Progress in Materials Science, Vol. 55, No. 8, pp. 759-839, 2010.
2. Chen, W., Liu, Z., and Schroers, J., “Joining of Bulk Metallic Glasses in Air”, Acta Materialia, Vol. 62, No. 1, pp. 49-57, 2014.
3. Schuh, C. A., Hufnagel, T. C., and Ramamurty U., “Mechanical Behavior of Amorphous Alloys”, Acta Materialia, Vol. 55, No. 12, pp. 4067-4109, 2007.
4. Argon, A. S., “Plastic Deformation in Metallic Glasses”, Acta Metallurgica, Vol. 27, No. 1, pp. 47-58, 1979.
5. Qiao, J. C., Wang, Y. J., Zhao, L. Z., Dai, L. H., Crespo, D., Pelletier, J. M., Keer, L. M., and Yao, Y., “Transition from Stress-Driven to Thermally Activated Stress Relaxation in Metallic Glasses”, Physical Review B, Vol. 94, No. 10, p. 104203, 2016.
6. Asadi Khanouki, M. T., Tavakoli, R., and Aashuri, H., “Effect of the Strain Rate on the Intermediate Temperature Brittleness in Zr-Based Bulk Metallic Glasses”, Journal of Non-Crystalline Solids, Vol. 475, pp. 172-178, 2017.
7. Asadi Khanouki, M. T., Tavakoli, R., and Aashuri, H., “Effect of Temperature on the Fracture Surface Morphology of Ti- and Zr-Based Bulk Metallic Glasses: Exploring Correlation Between Morphology and Plasticity”, Journal of Materials Science, Vol. 53, No. 14, pp. 10372-10382, 2018.
8. Zhang, X. Y., Yuan, Z. Z., Feng, X. L., Cui, L. Z., and Li, D. X., “Homogeneous Viscous Flow Behavior of a Cu-Zr Based Bulk Metallic Glass Composites”, Materials Science and Engineering A, Vol. 620, pp. 352-358, 2015.
9. Song, S. X., Lai, Y. H., Huang, J. C., and Nieh, T. G., “Homogeneous Deformation of Au-Based Metallic Glass Micropillars in Compression at Elevated Temperatures”, Applied Physics Letters, Vol. 94, No. 6, pp. 2007-2010, 2009.
10. Greer, A. L., Cheng, Y. Q., and Ma, E., “Shear Bands in Metallic Glasses”, Materials Science and Engineering R Reports, Vol. 74, No. 4, pp. 71-132, 2013.
11. Lewandowski, J. J., and Greer, A. L., “Temperature Rise at Shear Bands in Metallic Glasses”, Nature Materials, Vol. 5, No. 1, pp. 15-18, 2006.
12. Falk, M. L., and Langer, J. S., “Dynamics of Viscoplastic Deformation in Amorphous Solids”, Physical Review E, Vol. 57, No. 6, pp. 7192-7205, 1998.
13. Jiang, M. Q., and Dai, L. H., “On the Origin of Shear Banding Instability in Metallic Glasses”, Journal of the Mechanics and Physics of Solids, Vol. 57, No. 8, pp. 1267-1292, 2009.
14. Asadi Khanouki, M. T., Tavakoli, R., and Aashuri, H., “On the Origin of Intermediate Temperature Brittleness in La-Based Bulk Metallic Glasses”, Journal of Alloys and Compounds, Vol. 770, pp. 535-539, 2019.
15. Asadi Khanouki, M. T., Tavakoli, R., and Aashuri, H., “Serrated Flow During Inhomogeneous Bending Deformation of Bulk Metallic Glasses: From Self-Organized Critical to Chaotic Dynamics”, Journal of Non-Crystalline Solids, Vol. 505, pp. 62-71, 2019.
16. Lebyodkin, M., Dunin-Barkowskii, L., Bréchet, Y., Estrin, Y., and Kubin, L. P., “Spatio-Temporal Dynamics of the Portevin-Le Chatelier Effect: Experiment and Modelling”, Acta Materialia, Vol. 48, No. 10, pp. 2529-2541, 2000.
17. Pan, D., Inoue, A., Sakurai, T., and Chen, M. W., “Experimental Characterization of Shear Transformation Zones for Plastic Flow of Bulk Metallic Glasses”, Proceedings of the National Academy of Sciences of the United States of America, Vol. 105, No. 39, pp. 14769-14772, 2008.
18. ASM Handbook, Mechanical Testing and Evaluation, Vol. 8, No. 9, p. 2235, 2000.
19. Asadi Khanouki, M. T., Tavakoli, R., and Aashuri, H., “The Correlation Between Fracture Surface Morphology and Toughness/Ductility in Zr46(Cu4.5/5.5Ag1/5.5)46Al8 Bulk Metallic Glass”, New Process Material Engineering, Vol. 13, No. 2, pp. 1-16, 2019.
20. Asadi Khanouki, M. T., Tavakoli, R., and Aashuri, H., “The Effect of Temperature on the Fracture Surface Morphology and Ductility of La55Al25Ni5Cu10Co5 BMG”, Journal of Advanced Materials in Engineering (Esteghlal), Vol. 38, No. 2, pp. 11-24, 2019.
21. Spaepen, F., “A Microscopic Mechanism for Steady State Inhomogeneous Flow in Metallic Glasses”, Acta Metallurgica, Vol. 25, No. 4, pp. 407-415, 1977.
22. Schuh, C. A., and Nieh, T. G., “A Nanoindentation Study of Serrated Flow in Bulk Metallic Glasses”, Acta Materialia, Vol. 51, No. 1, pp. 87-99, 2003.
23. Dubach, A., Torre, F. H. D., and Loffler, J. F., “Constitutive Model for Inhomogeneous Flow in Bulk Metallic Glasses”, Acta Materialia, Vol. 57, pp. 881-892, 2009.
24. Mayr, S. G., “Activation Energy of Shear Transformation Zones: A Key for Understanding Rheology”, Physical Review Letters, Vol. 97, p. 195501, 2006.
25. Delogu, F., “Molecular Dynamics of Shear Transformation Zones in Metallic Glasses”, Intermetallics, Vol. 16, pp. 658-661, 2008.
26. Gurewitz, G., and Mukherjee, A. K., “The Strain Rate Sensitivity Values in Superplastic Deformation”, Materials Science and Engineering, Vol. 70, No. C, pp. 191-196, 1985.
27. Bhowmick, R., Raghavan, R., Chattopadhyay, K., and Ramamurty, U., “Plastic Fow Softening in a Bulk Metallic Glass”, Acta Materialia, Vol. 54, pp. 4221-4228, 2006.
28. Wang, C., Cao, Q. P., Wang, X. D., Zhang, D. X., Ramamurty, U., Narayan, R. L., and Jiang, J. Z., “Intermediate Temperature Brittleness in Metallic Glasses”, Advanced Materials, Vol. 29, p. 1605537, 2017.
29. Jiang, F., Jiang, M. Q., Wang, H. F., Zhao, Y. L., He, L., and Sun, J., “Shear Transformation Zone Volume Determining Ductile-Brittle Transition of Bulk Metallic Glasses”, Acta Materialia, Vol. 59, No. 5, pp. 2057-2068, 2011.
30. Schuh, C. A., Lund, A. C., and Nieh, T. G., “New Regime of Homogeneous Flow in the Deformation Map of Metallic Glasses: Elevated Temperature Nanoindentation Experiments and Mechanistic Modeling”, Acta Materialia, Vol. 52, No. 20, pp. 5879-5891, 2004.

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