Effects of processing parameters on properties of selective laser melting Mg–9%Al powder mixture

Selective Laser Melting of Magnesium and Magnesium Alloy Powders: A Review

“…Further, the interactions between laser sources and magnesium powder tracks under different processing conditions, including laser powers, scanning speeds, and irradiation modes (i.e., continuous wave and pulsed mode) were investigated and the processing window for the single track formation was established [56,57]. Also, several other investigations [58][59][60][61][62][63][64][65] have focused on developing processing windows based on the formability of magnesium and magnesium alloy powders such as Mg-9%Al, AZ91D, ZK60 and WE43 for fabricating single layer and multi-layer three dimensional parts. The details of the parameters used in these studies can be seen in Table 2.…”

“…Figure 3 presents an example of a process map developed for SLM Mg-9%Al powders in which several distinct zones are observed. Process map for Mg-9%Al, results as function of the range of laser powers and scan speeds (modified from reference [60]). …”

“…Zhang et al [60] studied the influence of laser energy densities on the densification of Mg-9%Al alloy parts by setting the laser power and laser scan speed using a continuous wave Nd:YAG laser. It was observed that the increase in laser energy density from 7.5 J/mm 2 to 15 J/mm 2 resulted in improved relative density of the melted samples from 74.5% to 82%.…”

“…During SLM processing of Mg-9%Al powders, Zhang et al [60], witnessed formation of cauliflower like grains with interconnected pores on the surface of the metal as shown in Figure 7 caused by a metal evaporation-solidification process. Though the majority of the laser energy was reflected because of low absorptivity of both magnesium and aluminium, adequate amount of Mg-Al powder could be melted and a molten pool was formed even at lower energy densities.…”

What triggers a microcrack in printed engineering parts produced by selective laser sintering on the first place?

“…Since the 1980s, when additive manufacture was invented, the industry has been growing and expanding, with new machines, processes and methods being developed every month. Selective Laser Sintering (SLS) [9,10,11] is a process which involves starting with an initial powder bed and then generating complex parts by Selective melting the cross section of a part layer by layer. The input of thermal energy via a laser beam provides the means by which the power both melts and consolidates together.…”