A strong coupling between the field theory of dislocation mechanics and heat conduction is proposed. The novel model, called the thermal field dislocation mechanics (T-FDM) model, is designed to study the dynamics of dislocations during rapid or gradual temperature changes in a body having a heterogeneous temperature distribution; for example, such conditions occur in a heat-affected crystalline solid during an additive manufacturing process. Thermal strains are uniquely separated into compatible and incompatible components via the Stokes-Helmholtz decomposition and the curl of the incompatible part of thermal strains is directly related to the areal dislocation density tensor. A dislocation density evolution (including transport) law is developed and shown to be related to the evolution of the curl of incompatible thermal strains. This relationship demonstrates that dislocation generation, annihilation, motion and/or interactions with other defects can be triggered due to transient temperature changes, and conversely an evolving dislocation density induces temperature changes. The model development is completed with constitutive laws derived from energetic and dissipative considerations. The advantages and consequences of the assumptions of the T-FDM model under rapidly changing temperatures, both spatially and temporally, are discussed. The T-FDM model is intended for application at the length scale where individual dislocations can be characterized. At this level, local thermodynamic equilibrium is found to be a reasonable assumption even for high rates of change of temperature such as those occurring during an additive manufacturing process. Some illustrative examples are presented to demonstrate the applicability of the model and to better understand some of the novel concepts proposed in this work.

提出了位错力学的场论与热传导之间的强耦合。这种新颖的模型称为热场位错力学（T-FDM）模型，旨在研究温度分布不均的物体在快速或渐进温度变化过程中位错的动力学。例如，这种情况发生在增材制造过程中的热影响结晶固体中。通过Stokes-Helmholtz分解将热应变唯一地分为兼容和不兼容的分量，并且不兼容的热应变部分的卷曲与面位错密度张量直接相关。位错密度演化（包括传输）定律得到发展，并显示出与不相容热应变的卷曲演化有关。这种关系表明，由于瞬态温度变化，可以触发位错的产生，an灭，运动和/或与其他缺陷的相互作用，相反，位错密度的变化会引起温度的变化。通过从能量和耗散考虑得出的本构定律完成模型开发。讨论了在空间和时间上快速变化的温度下T-FDM模型假设的优点和后果。T-FDM模型适用于可以表征单个位错的长度范围。在此水平上，即使对于较高的温度变化速率（例如在增材制造过程中发生的那些温度变化），也发现局部热力学平衡是一个合理的假设。