Heat treatment is a method of changing the properties of a material by changing its microstructure and grain morphology. It includes a series of heating and cooling processes that can significantly affect the physical and chemical properties of the material. So whether heat treatment will change the thermal conductivity of the material? This paper will discuss this problem from the micro and macro aspects.

From the microstructure, the thermal conductivity of the material is related to the order of the microstructure and the continuity of the lattice. For amorphous materials, the microstructure is disordered, so its thermal conductivity is poor. Heat treatment can crystallize the amorphous material through the process of solid solution, precipitation and recrystallization, forming an ordered crystal structure, thereby improving the thermal conductivity of the material.

For crystalline materials, its thermal conductivity is mainly affected by the crystal structure and grain size. There are lattice defects in the crystal, such as grain boundaries, dislocations and inclusions. These defects will cause energy scattering and hinder heat conduction, thus affecting the thermal conductivity of the material. Heat treatment can reduce the density of lattice defects through the process of grain boundary removal, dislocation elimination and inclusion precipitation, so as to improve the thermal conductivity of the material.

In addition, heat treatment can also change the grain size of the material. The size of the grain has an important influence on the thermal conductivity. When the grain size is large, the scattering and thermal resistance of the grain boundary are large, resulting in poor thermal conductivity of the material. The heat treatment can control the size of the grain through the process of grain boundary migration and crystal re-growth, so as to optimize the thermal conductivity of the material.

In addition to changes in the microstructure, heat treatment can also affect the macroscopic properties of the material, thereby changing the thermal conductivity of the material. For example, heat treatment can change the structure and density of the material, thereby affecting the thermal conductivity of the material. In addition, heat treatment can also change the crystal orientation and crystal morphology of the material, thereby affecting the heat conduction path and heat conduction resistance, thereby changing the thermal conductivity of the material.

It should be noted that the effect of heat treatment on the thermal conductivity of materials is a relatively complex process. Different heat treatment processes and conditions will have different effects, and the response of different materials to heat treatment is also different. In addition, heat treatment is also affected by factors such as the composition, composition and processing of the material. Therefore, in the heat treatment, it is necessary to consider the above factors, select the appropriate heat treatment process and conditions, in order to achieve the effective improvement of thermal conductivity.

In summary, heat treatment can change the microstructure and macroscopic properties of the material, thereby changing the thermal conductivity of the material. Specifically, heat treatment can optimize the crystal structure, grain size and grain boundary characteristics of the material, thereby reducing lattice defects and scattering, and improving thermal conductivity. In addition, heat treatment can also change the structure and density of the material, regulate the heat conduction path and heat conduction resistance, and further improve the thermal conductivity. However, the effect of heat treatment on the thermal conductivity of materials is a complex process, which requires comprehensive consideration of multiple factors and selection of appropriate heat treatment processes and conditions.