基于SPH的超音速火焰喷涂WC-12Co粒子速度对其沉积行为的影响

目的 以超音速火焰喷涂过程为基础，探究粒子撞击速度对粒子在基体上沉积行为的影响。方法 应用SPH方法，模拟分析WC-12Co粒子速度在400～800 m/s内，单个粒子在相同基体上的沉积行为。结果 粒子撞击速度与粒子扁平率、粒子基体结合面积、结合方式等有密切关系。随着粒子撞击速度的增加，基坑深度持续增大至最小深度的4.6倍，金属射流对提高粒子扁平化程度及粒子与基体的有效结合面积起到促进作用，总接触面积最大可达到原有效接触面积的2.7倍。撞击速度的提升使得有效塑性应变及应变区域增加，形变区域增大。同时，结合面温升总体增加，增强了粒子与基体的结合条件。沉积过程存在能量耗散，初始能量的提高有利于粒子与基体总能量的增加，强化了压实效应，进一步促进粒子与基体的结合。结论 在数值模拟选取的范围内，超音速火焰喷涂WC-12Co粒子的撞击速度越高，粒子与基体的结合状态越好。

Velocity of Particles on Deposition Behavior of WC-12Co Particles Sprayed by HVOF Based on SPH Method

Based on the HVOF process, this paper aims to investigate the effect of particles impact velocity on the deposition behavior of WC-12Co particles on the substrates. The deposition behavior of a single particle on the same substrate was simulated and analyzed using SPH method in the velocity range of 400~800 m/s. It is found that the particle impact velocity has a close relationship with the particle flattening rate, the bonding area, and the bonding method. With the increase of the impact velocity of the particles, the depth of the crater continuously increases to 4.6 times of the minimum depth. The metal jet promotes the improvement of the flattening degree of the particles and the effective bonding area between the particles and the substrates. The total contact area can reach 2.7 times of the original effective contact area at the maximum. With the increase of impact velocity, the effective plastic strain, strain area, and deformation area are increased. The temperature rise at that bonding surface increases, enhancing the bonding condition of the particles and the substrates. Energy dissipation exists in the deposition process. The increase of initial energy is beneficial to the increase of the total energy of particles and substrates, and strengthens the compaction effect and further promotes the combination of particles and substrates.