The key role of dislocation dissociation in the plastic behaviour of single crystal nickel-based superalloy with low stacking fault energy: Three-dimensional discrete dislocation dynamics modelling
The key role of dislocation dissociation in the plastic behaviour of single crystal nickel-based superalloy with low stacking fault energy: Three-dimensional discrete dislocation dynamics modelling
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位错解离在低堆垛层错能单晶镍基高温合金塑性行为中的关键作用：三维离散位错动力学建模
DOI：
10.1016/j.jmps.2013.07.011
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发表时间：
2013-12
影响因子：
5.3
通讯作者：
Zhenhuan Li
中科院分区：
文献类型：
--
作者：
Minsheng Huang;Zhenhuan Li
为了模拟低层错能单晶镍基高温合金(SCNBS)的变形过程，引入位错解离机制，扩展了三维离散位错动力学(3D-DDD)模型。目前的3D-DDD模拟结果表明，考虑位错解离后，前导部分可以有效地进入基质通道，而拖尾部分几乎不能滑入基质通道，这与已有的电子显微镜观察结果一致。为了确定位错是否发生解离，提出了一个基于临界渗流应力的判据。根据这一CPS准则，对于SCNBS，存在一个临界矩阵通道宽度。当沟道宽度小于该临界值时，位错倾向于解离为扩展组态，反之亦然。为了阐明位错解离对CPS的影响，对经典的Orowan公式进行了改进，引入了SFE。此外，目前的3D-DDD模拟还表明，如果忽略位错解离，低SFE的SCNBs的屈服应力可能被高估高达30%。考虑位错解离后，γ基质沟道宽度和γ‘析出物长度对SCNBs应力应变响应的尺寸效应显著增强。此外，由于SCNBS中两相组织的强烈约束作用，形成的结的形态与铜等单相晶体的形态有很大的不同。这些结果不仅对低SFE条件下SCNBs的两相组织分层微塑性机理有了明确的认识，而且有助于建立新的连续介质分层本构关系。
To model the deformation of single crystal nickel based superalloys (SCNBS) with low stacking fault energy (SFE), three-dimensional discrete dislocation dynamics (3D-DDD) is extended by incorporating dislocation dissociation mechanism. The present 3D-DDD simulations show that, consistent with the existing TEM observation, the leading partial can enter the matrix channel efficiently while the trailing partial can hardly glide into it when the dislocation dissociation is taken into account. To determine whether the dislocation dissociation can occur or not, a critical percolation stress (CPS) based criterion is suggested. According to this CPS criterion, for SCNBS there exists a critical matrix channel width. When the channel width is lower than this critical value, the dislocation tends to dissociate into an extended configuration andvice versa. To clarify the influence of dislocation dissociation on CPS, the classical Orowan formula is improved by incorporating the SFE. Moreover, the present 3D-DDD simulations also show that the yielding stress of SCNBSs with low SFE may be overestimated up to 30% if the dislocation dissociation is ignored. With dislocation dissociation being considered, the size effect due to the width of γ matrix channel and the length of γ′ precipitates on the stress–strain responses of SCNBS can be enhanced remarkably. In addition, due to the strong constraint effect by the two-phase microstructure in SCNBS, the configuration of formed junctions is quite different from that in single phase crystals such as Cu. The present results not only provide clear understanding of the two-phase microstructure levelled microplastic mechanisms in SCNBSs with low SFE, but also help to develop new continuum-levelled constitutive laws for SCNBSs.
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影响因子：
6
作者：
H. Fan;Zhenhua Li;Minsheng Huang
通讯作者：
H. Fan;Zhenhua Li;Minsheng Huang
DOI：
10.1016/s0921-5093(00)01725-1
发表时间：
2001-07
影响因子：
6.4
作者：
B. Devincre;L. Kubin;C. Lemarchand;R. Madec
通讯作者：
B. Devincre;L. Kubin;C. Lemarchand;R. Madec
DOI：
10.1088/0965-0393/18/1/015005
发表时间：
2009
影响因子：
1.8
作者：
T. Tinga;W. Brekelmans;Mgd Marc Geers
通讯作者：
T. Tinga;W. Brekelmans;Mgd Marc Geers
影响因子：
1.6
作者：
C. Déprés;C. Robertson;M. Fivel
通讯作者：
C. Déprés;C. Robertson;M. Fivel
DOI：
10.1016/0956-7151(92)90195-k
发表时间：
1992-01-01
期刊：
ACTA METALLURGICA ET MATERIALIA
影响因子：
--
作者：
POLLOCK, TM;ARGON, AS
通讯作者：
ARGON, AS