Low pressure cold spray (LP-CS) is a kind of cold spray (CS) technology. Due to lower gas pressure, particles are difficult to deposit using LP-CS. The particles should be softened by heating of the carrier gas (200 °C–600 °C) in the Laval nozzle to compensate for this deficiency. In this study, the morphology of particles ejected from the Laval nozzle was observed using a scanning electron microscope (SEM), and the aggregation phenomenon between particles was obtained for the first time. With increasing the carrier gas temperature, the particle morphology tended to be irregular gradually due to aggregation and this phenomenon cannot be ignored. Based on this phenomenon, an aggregated particle model was established and the deposition behaviour was investigated by a coupled thermomechanical Eulerian method. The results show that the equivalent plastic strain (PEEQ) of the aggregated particle mainly depends on the particle velocity, and the change of temperature depends more on the original particle temperature. Compared with the individual particles, the bonding between the aggregated particle and substrate is poor at the middle position. In addition, the multi-particles deposition simulation indicates that the formation of coating pores could be inhibited to some extent by the phenomenon of aggregation between particles.

低压冷喷涂（LP-CS）是一种冷喷涂（CS）技术。由于较低的气压，使用LP-CS难以沉积颗粒。应该通过加热Laval喷嘴中的载气（200°C–600°C）来软化颗粒，以弥补这一不足。在这项研究中，使用扫描电子显微镜（SEM）观察了从拉瓦尔喷嘴喷出的颗粒的形态，并首次获得了颗粒之间的聚集现象。随着载气温度的升高，由于聚集而使颗粒形态逐渐趋于不规则，这种现象不容忽视。基于此现象，建立了聚集颗粒模型，并通过热力学欧拉耦合方法研究了沉积行为。结果表明，聚集颗粒的等效塑性应变（PEEQ）主要取决于颗粒速度，而温度的变化更多地取决于原始颗粒温度。与单个颗粒相比，聚集颗粒与基材之间的结合在中间位置较差。另外，多颗粒沉积模拟表明，涂层之间的聚集现象可以在一定程度上抑制涂层孔的形成。