Laser powder bed fusion of a near-eutectic Al–Fe binary alloy: Processing and microstructure

Processability and Optimization of Laser Parameters for Densification of Hypereutectic Al–Fe Binary Alloy Manufactured by Laser Powder Bed Fusion

“…The relative density increased at higher P values (Figure 5), whereas cracks (macroscopically propagating parallel to the powder bed plane) occurred in the built samples when P > 140 W and v > 1.0 m•s −1 (Figure 2a,c). The suitable ranges of P and v for manufacturing dense Al-15%Fe alloy samples are different from the optimized parameters reported for other Al alloys [16][17][18]20,24,27,30]. Figure 8 presents the laser parameter ranges for manufacturing Al-15%Fe alloy samples with high relative densities above 95%, together with the process windows for other types of alloys in the literature [16][17][18]20,24,27,30].…”

“…Thus, a higher laser scan speed would enhance the formation of microscale solidification cracks in the L-PBF process, assisting the process to form macroscopic lateral cracks in the built Al-15%Fe alloy samples, as presented in Figure 2c. Laser power (P) and scan speed (v) for manufacturing the Al-15%Fe alloy samples with high relative densities above 95%, together with the process windows for manufacturing other alloy samples reported in the literature [16][17][18]20,24,27,30].…”

“…An extensive body of literature exists regarding the effect of L-PBF process parameters on the relative density of manufactured metal and alloy samples [16][17][18]20,24,27,30,34,49]. The volumetric energy density (E) [34,50] has been widely used to integrate various L-PBF processing parameters of P, v, hatch distance between adjacent laser scanning tracks (h), and powder layer thickness (t):…”

“…In addition, v also affects the energy density irradiated on the bedded powder layer and causes variation in the effective distance of heat transfer into the powder layer. It has been demonstrated that the deposited energy density model [52] considering thermal diffusivity was appropriate for optimizing the laser parameter to manufacture fully dense samples using powders of Al-2.5%Fe alloy [30] and maraging steel [34]. The deposited energy density (∆H) is defined by the enthalpy at melting (h s ), laser absorptivity (A), thermal diffusivity (D), and laser spot size (σ) as follows:…”

“…In fact, the influence of L-PBF process parameters on porosity and cracking (L-PBF processability) had been extensively studied in the cases of Al-Si-based alloys [10,[16][17][18] and age-hardenable wrought-type alloys (the 2xxx, 6xxx, and 7xxx series) [19][20][21][22][23][24][25][26][27][28][29]. In comparison, similar research for the Al-Fe alloys remains limited [30], although a few reports considered application of the L-PBF process to the Al-Fe-based alloys [31,32].…”