Selective Laser Melting Defects: Morphology of Defects Due to Lack of Fusion andEvaporation Pores

Selection of the proper process parameters is one of theunsolved challenges in Selective Laser Melting (SLM)methods. Although the SLM technique has been successfullyapplied to many alloys, the parts produced using thistechnique are vulnerable to defects such as pores and lack offusion. However, processes parameters can be managed toproduce a part with proper mechanical properties whilepreventing the formation of defects. The purpose of thisresearch is to determine the influence of process factors suchas laser speed and power on the location and amount of theun-melted zones (UMZ) and the evaporated zones (EVZ). Itis also aim to increase accuracy of simulation by consideringevaporation in the thermal analysis of SLM. The thermalproperties of all five phases (powder, melting, mushy zone,solidified, and vapor) were thought to be temperaturedependent.In a comprehensive example, different scanspeeds and laser powers were investigated. The resultsrevealed that as the scan speed increased or the laser powerdecreased, the amount of UMZ decreased whereas theamount of EVZ increased. It was also discovered that theUMZ was more prevalent in the early layers and the PZ wasmore prevalent in the late layers.