He Hong, Ma Shangyi, Wang Shaoqing
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China.
Materials (Basel). 2021 Dec 26;15(1):156. doi: 10.3390/ma15010156.
Heat treatment is a necessary means to obtain desired properties for most of the materials. Thus, the grain boundary (GB) phenomena observed in experiments actually reflect the GB behaviors at relatively high temperature to some extent. In this work, 405 different GBs were systematically constructed for body-centered cubic (BCC) metals and the grain boundary energies (GBEs) of these GBs were calculated with molecular dynamics for W at 2400 K and -Ti at 1300 K and by means of molecular statics for Mo and W at 0 K. It was found that high temperature may result in the GB complexion transitions for some GBs, such as the Σ11{332}{332} of W. Moreover, the relationships between GBEs and sin() can be described by the functions of the same type for different GB sets having the same misorientation axis, where is the angle between the misorientation axis and the GB plane. Generally, the GBs tend to have lower GBE when sin() is equal to 0. However, the GB sets with the <110> misorientation axis have the lowest GBE when sin() is close to 1. Another discovery is that the local hexagonal-close packed phase is more likely to form at the GBs with the lattice misorientations of 38.9°/<110>, 50.5°/<110>, 59.0°/<110> and 60.0°/<111> for -Ti at 1300 K.
对于大多数材料而言，热处理是获得所需性能的必要手段。因此，实验中观察到的晶界（GB）现象在一定程度上实际反映了较高温度下的晶界行为。在这项工作中，为体心立方（BCC）金属系统构建了405个不同的晶界，并通过分子动力学计算了这些晶界在2400 K下W和1300 K下α-Ti的晶界能（GBE），以及通过分子静力学计算了0 K下Mo和W的晶界能。研究发现，高温可能导致某些晶界的晶界复杂性转变，例如W的Σ11{332}{332}晶界。此外，对于具有相同取向差轴的不同晶界集，GBE与sin(θ)之间的关系可以用同一类型的函数来描述，其中θ是取向差轴与晶界平面之间的夹角。一般来说，当sin(θ)等于0时，晶界往往具有较低的GBE。然而，当sin(θ)接近1时，具有<110>取向差轴的晶界集具有最低的GBE。另一个发现是，在1300 K下，对于α-Ti，在晶格取向差为38.9°/<110>、50.5°/<110>、59.0°/<110>和60.0°/<111>的晶界处更有可能形成局部六方密堆积相。
