工艺参数对Ni/Fe金属热喷涂影响的分子动力学模拟

Molecular Dynamics Simulation of the Effect of Process Parameters on Ni/Fe Metal Thermal Spraying

摘要:

采用分子动力学模拟方法研究不同工艺参数下热喷涂材料的沉积现象。模拟温度、团簇尺寸和喷涂速度对Fe基体上Ni团簇沉积的影响，分析团簇的形貌和基底的亚表面损伤。结果表明，在Ni团簇升温过程中，熔点随团簇尺寸增大而增高，Ni团簇在1800 K左右完全熔融。喷涂过程中，基体因冲击力至无序原子呈“山”型。此外，喷涂速度在沉积过程中起重要作用。在较低喷涂速度下，基体的展平比较低，但在较高喷涂速度下，基体受团簇冲击后会出现空位和原子团簇等缺陷。因此，热喷涂过程存在临界喷涂速度机制。

Abstract:

Molecular dynamics simulations were performed to study the deposition of the thermal spraying material under different process parameters. The effects of temperatures, cluster size, and spraying speed on the deposition of Ni clusters on the Fe substrate were examined. The morphology of clusters and the subsurface damage of the substrate were analyzed. The results show that in the heating-up process of Ni cluster, the melting point becomes higher with the increase of cluster size, and the complete melting temperature of Ni cluster is about 1800 K. During the spraying process, the matrix shows a “mountain” shape due to the impact force to disordered atoms. Furthermore, it is also found that spraying speed plays an important role in the deposition process. At lower spraying speed, the flattening ratio decreases again, but at higher spraying speed, the substrate has defects, such as vacancy and atomic cluster after the impact of clusters. Thus, there is a critical spraying speed mechanism in thermal spraying.