PSI - Issue 69

Mohammadjavad Abdollahzadeh et al. / Procedia Structural Integrity 69 (2025) 2–19

16

contribute significantly to residual stress formation within the material. Uneven cooling rates between the top and bottom regions, as evidenced by the decreasing peak temperature closer to the substrate, may result in tensile stresses near the surface and compressive stresses in deeper layers, affecting the overall structural integrity.

Fig.12: temperature histories of the five marker points at laser power equal to 150 W and scan speed equal to 115 cm/s. As laser moves and transfer energy to the powders, powder absorb the energy and melt after a while. Also, as laser passes over the surface the peak temperature goes up until it reaches an almost stable and constant value. From the figure it can be obtained that from point C to A the peak temperature a bit reduced. The reason can be related to the position of the points. They are probably placed in a location where there is a void space which means that in that area there is a gas phase as well which can affect the temperature.