selective laser melting defects: morphology of defects due to lack of fusion and evaporation pores

Selection of the proper process parameters is one of the unsolved challenges in selective laser melting (slm) methods. although the slm technique has been successfully applied to many alloys, the parts produced using this technique are vulnerable to defects such as pores and lack of fusion. however, processes parameters can be managed to produce a part with proper mechanical properties while preventing the formation of defects. the purpose of this research is to determine the influence of process factors such as laser speed and power on the location and amount of the un-melted zones (umz) and the evaporated zones (evz). it is also aim to increase accuracy of simulation by considering evaporation in the thermal analysis of slm. the thermal properties of all five phases (powder, melting, mushy zone, solidified, and vapor) were thought to be temperature-dependent. in a comprehensive example, different scan speeds and laser powers were investigated. the results revealed that as the scan speed increased or the laser power decreased, the amount of umz decreased whereas the amount of evz increased. it was also discovered that the umz was more prevalent in the early layers and the pz was more prevalent in the late layers.