Figure 6
A high-speed X-ray image from a representative LPBF experiment. (a) The vapor depression, (b) the melt pool, (c) keyhole porosity, (d) ejected powder and (e) spatter or molten metal ejected from the melt pool. The substrate and the powder were composed of Al–Si10–Mg. The substrate thickness (along the X-ray beam direction) was 800 µm and the powder size was between 15 and 45 µm. The laser power was set at 520 W and the scanning speed was 0.6 m s−1. X-ray images were recorded at 30173 Hz with an effective exposure time of 100 ps. Some powder clusters adhered to the outside of the holder and did not contribute to the laser-melting and solidification processes. These clusters can be observed on the left and right of the vapor depression. |