用分子动力学方法对铜纳米丝的应变率效应和尺寸效应进行了模拟研究.结果表明,随着加载应变率的增大,铜纳米丝从低应变率下的静态响应逐渐呈现出较高应变率下的准静态以及高应变率下的动态响应特征,其变形机制以及应力-应变曲线的形态也随之发生变化.在静态和准静态区域,位错运动是铜纳米丝塑性变形的主要来源,而在高应变率动态加载时,铜纳米丝出现整体结构的非晶化,最大屈服应力也随着应变率的升高而增大,强化现象明显.当铜纳米丝的截面尺寸变化时,其弹性模量、屈服应力以及屈服应变、进入强化区域的临界应变率等都发生相应的变化,尺寸效应显著.
参考文献
| [1] | M.A.Meyers, Dynamic Behavior of Materials (John Wiley & Sons, Inc, Wiley-Interscience Publication,1994) p.1 |
| [2] | Woei-Shyan Lee, Chi-Feng Lin. Impact Properties and Microstructure Evolution of 304L Stainless Steel.Materials Science & Engineering A, 308, 124(2001) |
| [3] | R.J.Clifton. Dynamics Plasticity. Journal of Applied Mechanics, 50, 941(1983) |
| [4] | R.K.Soong, G.D.Bachand, H.P. Neves, A.G.Olkhovets, H.G.Craighead, C.D.Montemagno, Powering an Inorganic Nanodevice with a Biomolecular Motor. Science, 290, 1555(2000) |
| [5] | H.Noji, R.Yasuda, M.Yoshlda, K.K.Jr, Direct observation of the rotation of F1-ATPase, Nature, 386(20),299(1997) |
| [6] | Doyama, Masao; Nozaki, Tadatoshi; Kogure, Yoshiaki; Yokotsuka, Tatsuo., Plastic deformation of pure silicon nanocrystals by molecular dynamics. Nanostructured Materials, 12, 333(1999) |
| [7] | H.Mehrez, S.Ciraci, Yielding and fracture mechanisms of nanowires, PRB, 56(19), 12632(1997) |
| [8] | H.I.Yue Qi, Tahir Cagin, Konrad Samwer, W.L.Johnson, W.A.Goddard Ⅲ, Strain rate induced amorphization in metallic nanowires, PRL, 82(14), 2900(1999) |
| [9] | Paulo S.Branicio, Jose-Pedro Rino, Large deformation and amorphization of Ni nanowires under uniaxial strain: A molecular dynamics study, PRB, 62(24), 16950(2000) |
| [10] | M.F.Horstemeyer, M.I.Baskes, S.J.Plimpton, Length scale and time scale effects on the plastic flow of FCC metals, Acta mater, 49, 4363(2001) |
| [11] | S.Nose, A unified formulation of the constant temperature molecular dynamics methods. J.Chem. Phys.,84(1), 551(1984) |
| [12] | W.G.Hoover, Canonical dynamics: Equilibrium phase-space distributions. Physical Review A, 31(3),1695(1985) |
| [13] | M.P. Allen, D.J.Tildesley, Computer Simulation of liquids (Oxiford, Clarendon Press, 1987) p.78 |
| [14] | M.Parrinello, A.Rahman, Polymorphic Transitions in Single Crystals: A New Molecular Dynamics Method.Journal of Applied Physics, 52(12), 7182(1981) |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%