Directed Energy Deposition is a common Additive Manufacturing technique used for its high deposition rate, but the interactions between the powder stream and the laser beam are still not completely understood. It is known that the powder particles heat up in the laser beam and some theoretical models predict that they can reach vaporization temperature and are significantly accelerated by the recoil pressure. In order to learn more about these phenomena, AlSi10Mg powder streams were observed with a high-speed camera at different laser powers and a particle-tracking software was used to measure the speed of the particles. The results show no significant increase of particle speed near the powder focus where the powder is processed, nor further below the powder focus. The high initial speed of the particles results in a short travelling time through the laser beam and in a very small effect of the recoil pressure.