Shock wave experiments show that many annealed face-centered cubic metals exhibit an anomalously increasing yield strength with temperature at high strain rates. Such an increase is usually associated with the multiplication of dislocations in the phonon friction mode, which slows with temperature. However, the effect of temperature on the structure of the shock wave and the yield strength of metal crystals, including those with microstructure, remains elusive. In this paper, we perform molecular dynamic simulations of shock-wave loading for [110] and [111] copper crystals of 0.45 and $0.80$  $\mathrm{\mu m}$ length in a wide range of temperatures between 100 and $1100$  $\mathrm{K}$ to understand the role of temperature and preexisting dislocations on the Hugoniot Elastic Limit (HEL). We show that, in ideal copper crystals, the elastic precursor exhibits a form of plateau, and the HEL almost does not change with shock propagation distance. However, at higher impacts, the perturbations of an elastic precursor are observed leading to fluctuations in the HEL value. We show that temperature dependencies of the HEL are strongly anisotropic. The HEL values tend to decrease with temperature for [110] perfect copper crystals, and to increase with temperature for [111] copper crystals. This surprising result is explained by the presence of dislocation substructures in a plastic wave in [110] crystals, which reduces the mobility of dislocations and makes the process of dislocation nucleation more dominant than in [111] crystals. Preexisting dislocations in copper crystals allow the HEL to decay much faster than in ideal crystals. In contrast to ideal [110] crystals, [110] crystals with dislocations exhibit increasing HEL values with temperature, as do [111] crystals. We find that the HEL dependence could be well approximated by a power law, but the decay power changes as the wave propagates. The decay power values lie between $0.5$ to $0.7$ in the second stage for both [110] and [111] crystals, which is consistent with experimental results with polycrystalline annealed copper. Our findings extend our understanding of temperature-dependent mechanical properties of materials under high strain rate and crystal plasticity.

冲击波实验表明，许多退火的面心立方金属在高应变率下表现出随温度异常增加的屈服强度。这种增加通常与声子摩擦模式中位错的增加有关，它随着温度的升高而减慢。然而，温度对冲击波结构和金属晶体（包括具有微观结构的晶体）的屈服强度的影响仍然难以捉摸。在本文中，我们对 0.45 和 [110] 和 [111] 铜晶体的冲击波加载进行了分子动力学模拟，$0.80$  $\mathrm{微米}$长度在 100 到$1100$  $\mathrm{钾}$了解温度和预先存在的位错对 Hugoniot 弹性极限 (HEL) 的作用。我们表明，在理想的铜晶体中，弹性前体呈现出一种平台形式，并且 HEL 几乎不随冲击传播距离而变化。然而，在较高的影响下，观察到弹性前体的扰动导致 HEL 值波动。我们表明 HEL 的温度依赖性具有很强的各向异性。[110] 完美铜晶体的 HEL 值趋于随温度降低，而 [111] 铜晶体的 HEL 值趋于随温度升高。这个令人惊讶的结果可以解释为存在[110] 晶体中塑性波中的位错亚结构，这降低了位错的迁移率并使位错成核过程比 [111] 晶体中更占优势。铜晶体中预先存在的位错使 HEL 的衰减速度比理想晶体快得多。与理想的 [110] 晶体相比，具有位错的 [110] 晶体表现出随温度升高的 HEL 值，[111] 晶体也是如此。我们发现 HEL 依赖性可以通过幂律很好地近似，但衰减功率随着波的传播而变化。衰减功率值介于$0.\mathrm{5个}$到$0.7$[110]和[111]晶体在第二阶段，这与多晶退火铜的实验结果一致。我们的发现扩展了我们对高应变率和晶体塑性下材料的温度依赖性机械性能的理解。