This could be attributed to the formation of high-density dislocations and vacancies during cold deformation, which provided a high diffusion path of carbon atoms.

• 其原因是在冷变形过程中产生了高密度位错以及大量空位等缺陷，为碳原子的扩散提供了高速率扩散通道，促进了碳原子的扩散。