Intrinsic and extrinsic effects on the brittle-to-ductile transition in metallic glasses
Intrinsic and extrinsic effects on the brittle-to-ductile transition in metallic glasses
复制标题
金属玻璃脆塑转变的内在和外在影响
DOI：
10.1063/5.0020201
复制
发表时间：
2020-09
影响因子：
3.2
通讯作者：
J. Eckert
中科院分区：
文献类型：
--
作者：
X. Yuan;D. Şopu;F. Moitzi;K.K. Song;J. Eckert
采用大尺度分子动力学模拟方法研究了冷却速率、温度和应变速率对Cu64Zr36金属玻璃拉伸变形行为的影响。在样品制备过程中的淬火速率的增加，以及温度或施加的应变速率的增加，影响剪切转变区（STZ）的激活，因此，剪切带的过程，这最终导致脆性到韧性的转变在变形行为的MG。通过对势能面上鞍点的取样，得到了随淬火速率增加镁合金塑性增强的定量解释。高淬灭速率导致较低的能量势垒激活的局部原子重排（STZ）相比，在低淬灭速率获得的MG。虽然玻璃态结构并没有表现出显着的变化，随着温度的升高，原子的动能急剧增加，这使得原子很容易重新排列，因此，均匀的热激活STZ的可能性增加。最后，大量的STZ也可以通过在高应变速率下的变形激活时，大量的弹性能量存储在玻璃基质中。因此，高密度的STZ事件，因此，一个更复杂的渗流过程的结果在一个低的概率应变局部化和临界剪切带的形成。我们的研究结果提供了一个原子的理解在金属玻璃中的应变局部化机制，并揭示了更多的脆韧性转变。
The effects of cooling rate, temperature, and applied strain rate on the tensile deformation behavior of a Cu 64 Zr 36 metallic glass (MG) are investigated using large-scale molecular dynamics simulations. An increase in the quenching rate during sample preparation, as well as an increase of the temperature or the applied strain rate, affects the activation of shear transformation zones (STZs) and, consequently, the shear-banding processes, which ultimately causes a brittle-to-ductile transition in the deformation behavior of MGs. A quantitative interpretation for the observed enhanced ductility in MGs with an increasing quenching rate is obtained by sampling the saddle points on the potential energy surface. High quenching rates lead to lower energy barriers for activation of a local atomic rearrangement (STZ) as compared to those MGs obtained at low quenching rates. Although the glassy structure does not show significant variations with increasing temperature, the kinetic energy of the atoms increases dramatically, which allows the atoms to rearrange easily; therefore, the probability of homogeneous thermal activation of STZs increases. Finally, a large number of STZs can also be activated by deformation at high strain rates when a large amount of elastic energy is stored in the glassy matrix. Consequently, a high density of STZ events and, therefore, a more complex percolation process results in a low probability for strain localization and formation of critical shear bands. Our results provide an atomistic understanding for the strain localization mechanisms in metallic glasses and shed more light on the brittle-to-ductile transition.
登录
查看更多内容
影响因子：
1.6
作者：
A. Sergueeva;N. Mara;J. Kuntz;E. Lavernia;A. K. Mukherjee *
通讯作者：
A. Sergueeva;N. Mara;J. Kuntz;E. Lavernia;A. K. Mukherjee *
DOI：
10.1002/9781118801017.ch7.10
发表时间：
2021-02
期刊：
Encyclopedia of Glass Science, Technology, History, and Culture
影响因子：
--
作者：
D. V. Louzguine-Luzgin;A. Inoue
通讯作者：
D. V. Louzguine-Luzgin;A. Inoue
DOI：
10.1016/0001-6160(79)90055-5
发表时间：
1979-01-01
期刊：
ACTA METALLURGICA
影响因子：
--
作者：
ARGON, AS
通讯作者：
ARGON, AS
影响因子：
9.4
作者：
F. Moitzi;D. Şopu;D. Holec;D. Perera;N. Mousseau;J. Eckert
通讯作者：
F. Moitzi;D. Şopu;D. Holec;D. Perera;N. Mousseau;J. Eckert
影响因子：
1.2
作者：
Y. Yokoyama;K. Fujita;A. Yavari;A. Inoue
通讯作者：
Y. Yokoyama;K. Fujita;A. Yavari;A. Inoue