Materials Transactions, Vol.51 No.09 (2010) pp.1504-1509
© 2010 The Japan Institute of Metals
Enhancement of Plasticity of Highly Density-Fluctuated Cu-Zr Amorphous Alloy
1School of Mechanical Engineering, Kumoh National Institute of Technology, Gumi, Gyeongbuk 730-701, Korea
2Department of Mechanical Engineering, Osaka University, Osaka 565-0871, Japan
3Department of Mechanical Engineering, Iwate University, Morioka 020-8550, Japan
This study explores the plastic deformability of highly density-fluctuated states due to the different thermal quenching process of the binary amorphous metals, Zr67Cu33, with embedded nanocrystals, Zr2Cu. To know the effect of local structural fluctuation, we prepare 5 computational models with Zr2Cu-nanocrystals that undergo rapid heat up and cool down. The region of nanocrystals is corresponding to the dense area because the intrinsic density of crystal is greater than that of amorphous structure. Due to the distribution of nanocrystals, the artificially constructed models have highly density-fluctuated structures (called ``structural-inhomogeneity''). Strain localization during plastic deformation is much retarded at structural-inhomogeneous model in tensile loading. We found that structural-inhomogeneity promotes more homogenous deformation (call ``deformable-homogeneity'', that is, retarded strain localization) even in globally recognized elastic region, while structural-homogeneity (almost close to pure amorphous structure) makes catastrophic inhomogeneous deformation (catastrophic shear band).
(Received 2010/4/22; Accepted 2010/6/28; Published 2010/8/11)
Keywords: zirconium-copper binary amorphous alloy, highly density-fluctuated state, Zr2Cu-nanocrystals, shear band, molecular dynamics simulation, plane stress condition
Table of Contents
- W. Klement, R. H. Wilens and P. Duwez: Nature 187 (1960) 869–870.
- W. L. Johnson: MRS Bull 24 (1999) 42–56.
- C. A. Pampillo: J. Mater. Sci. 10 (1975) 1194–1227.
- F. Spapen: Acta Metall. 25 (1977) 407–415.
- H. J. Leamy, H. S. Chen and T. T. Wang: Met. Trans. 3 (1972) 699–708.
- J. J. Lewandowski and A. L. Greer: Nature 5 (2006) 15–18.
- C. C. Hays, C. P. Kim and W. L. Johnson: Phys. Rev. Lett. 84 (2000) 2901.
- C. Fan and A. Inoue: Appl. Phys. Lett. 77 (2000) 46–48.
- K. F. Yao, F. Ruan, Y. Q. Yang and N. Chen: Appl. Phys. Lett. 88 (2006) 122106-1–3.
- H. Kato, T. Hirano, A. Matsuo, Y. Kawamura and A. Inoue: Scr. Mater. 43 (2000) 503–507.
- D. Pan, Y. Yokoyama, T. Fujita, Y. H. Liu, S. Kohara, A. Inoue and M. W. Chen: Appl. Phys. Lett. 95 (2009) 141909.
- T. Nasu, M. Sasaki, T. Usuki, M. Sekine, Y. Takigawa, K. Higashi, S. Kohara, M. Sakurai, Z. Wei and A. Inoue: J. Alloy. Compd. 483 (2009) 589–592.
- M. Wakeda, Y. Shibutani, S. Ogata and J. Park: Appl. Phys. A 91 (2008) 281–285.
- J. Lee, Y. Kim, J. Ahn, H. Kim, S. Lee and B. Lee: Acta Mater. 52 (2004) 1525–1533.
- W. H. Jiang and M. Atzmon: Scr. Mater. 54 (2006) 333–336.
- Y. Shi and M. Falk: Appl. Phys. Lett. 86 (2005) 011914-1–3.
- Y. Shi and M. Falk: Phys. Rev. Lett. 95 (2005) 095502-1–4.
- Y. Shi and M. Falk: Phys. Rev. B 73 (2006) 214201-1–10.
- M. J. Demkowicz and A. S. Argon: Phys. Rev. B 72 (2005) 245205-1–16.
- T. Nagase and Y. Umakoshi: Scr. Mater. 48 (2003) 1237–1242.
- S. Kobayashi, K. Maeda and S. Takeuchi: Acta Metall. 128 (1980) 1641–1652.
- M. Asato, R. Tamura, N. Fujima and T. Hoshino: Mat. Sci. Forum 561–565 (2007) 1259–1262.
- E. Saksl, H. Franz, P. Jovari, K. Klementiev, E. Welter, A. Ehnes, J. Saida, A. Inoue and J. Z. Jiang: Appl. Phys. Lett. 83 (2003) 3924–3926.
- All models used in this study are relaxed at below melting temperature. Some part of placed crystals already goes back to pure amorphous structures, but others still remain in density fluctuation structure even at below melting temperature. It means that there are no clear boundaries discriminating the crystallites and density fluctuation which is not a crystalline phase. Therefore, as mentioned in the main text, we treat density fluctuation and crystallites in an identical manner.
- J. Park, Y. Shibutani, S. Ogata and M. Wakeda: Mater. Trans. 46 (2005) 2848–2855.
- M. Wakeda: Doctoral dissertation, Osaka University, (2008).
- P. H. Mott, A. S. Argon and U. W. Suter: J. Comput. Phys. 101 (1992) 140–150.
- J. Park and Y. Shibutani: Intermetallics 15 (2007) 187–192.
© 2010 The Japan Institute of Metals
Comments to us :