Molecular Dynamics Simulation of Ti and Ni Particles on Ti Substrate in the Cold Gas Dynamic Spray (CGDS) Process

2015 ◽  
Vol 828-829 ◽  
pp. 453-460 ◽  
Author(s):  
Terence Malama ◽  
Agripa Hamweendo ◽  
Ionel Botef

This paper presents simulation of molecular dynamics for the deposition of Titanium (Ti) and Nickel (Ni) particles on Ti substrate during Cold Gas Dynamic Spray (CGDS) process. The influencing factors of the deposition process, such as particle incident velocity, particle size and particle temperature are taken into consideration. Ti and Ni were selected because of their potential applications in the aerospace, marine and bio-medical industries. CGDS is preferred because it is a state of the art technique by which coatings are created without significant heating of the sprayed powder. In CGDS, particles are accelerated to supersonic velocities using a high speed gas stream. However, there are inherent difficulties in relating particle deposition characteristics with influencing factors of the deposition process. Moreover, there is limited literature on molecular dynamics simulation of CGDS process. For this reason, this paper develops a simulation process for Ti and Ni particles under influence of many factors using molecular dynamics. In this process, particles are allowed to interact for a short time, giving a view of their motion. The trajectories of these particles are determined by numerically solving the Newton's equations of motion for a system of interacting particles, in which the forces between the particles are defined. The results of the simulation process show that higher incident velocities and larger particle sizes result in stronger interface between the particle and the substrate. Further, higher temperatures of the substrate and particles improve the bond strength.

Author(s):  
Hong Gao ◽  
Liangju Zhao ◽  
Danling Zeng ◽  
Lijuan Gao

Cold gas spray is a relatively new coating technique by which coatings can be formed without significant heating of the sprayed powder. In contrast to the conventional thermal spray processes, such as flame, arc, and plasma spraying, in cold spraying there is no melting of particles prior to impact on the substrate. In cold spray, particles are accelerated to a very high velocity by a flowing gas with supersonic speed and the temperature of spray particles is much lower than its melting point. However, being accomplished in so short an interval, the impact and deposition processes are difficult to be observed by experimental ways. Using molecular dynamics simulation, the deposition of nano-scale Au clusters on Au (001) surface was studied. The many-body potential is used to simulate the interatomic force between the atoms. By taking “snapshot”, the impact, deposition process and the final appearances of the cluster and the substrate were observed directly. It is found that both the substrate and the cluster deform and lose the crystalline structure. But after reconstruction and relaxation, both of them recover the crystalline structure. By calculating the temperatures of the substrate and the local area influenced by impinging, it is found that the melt phenomenon occurs during impact and deposition, whereas the temperature of the rest region of the substrate is still below the melt point. In addition, the influence factors on deposition, such as incident velocity and the size of the cluster, are discussed in the paper. Simulation results show that the higher incident velocity or the larger size of the cluster could result in stronger interaction between the substrate and the cluster owing to the higher kinetic energy of the cluster.


2014 ◽  
Vol 898 ◽  
pp. 41-46
Author(s):  
Xiao Gang Jian ◽  
Yun Hua Zhang

This paper briefly reviews the overseas and domestic research status of the mechanics of hetero film-substrate interface based on molecular dynamics simulation, on this basis building the accurate model of diamond coatings/WC interface and executing the molecular dynamic simulation, exactly measuring the adhesive strength of the diamond coatings/WC interface, finally exploring the influence of interface scales on the adhesive strength of the diamond coatings/WC interface and verifying the feasibility of studying the microscopic structure by molecular dynamics simulation to characterize the mechanical properties of macrostructure, which has important significance for optimizing deposition process of diamond coatings to improve the adhesive strength of the interface.


2005 ◽  
Vol 14 (2) ◽  
pp. 183-186 ◽  
Author(s):  
Ha Yong Lee ◽  
Young Ho Yu ◽  
Young Cheol Lee ◽  
Young Pyo Hong ◽  
Kyung Hyun Ko

2014 ◽  
Vol 140 (4) ◽  
pp. 044326 ◽  
Author(s):  
Philipp Thaler ◽  
Alexander Volk ◽  
Martin Ratschek ◽  
Markus Koch ◽  
Wolfgang E. Ernst

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