Figure 13 D.O.E Surface Plot Showing the Effect of Laser Parameters on the Microhardness of AlTiCrFeCoNi HEA (a) Stage 1 of Experiments (b) Stage 2 of Experiments
Consequently, the AlTiCrFeCoNi alloy’s had higher hardness values after the first stage of experiments but showed a decline at the second stage of experiments with an average hardness ranging from 811-387 HV compared to AlCoCrFeNiCu HEA which ranged from 389-837 HV after stage one and two of the experiments. Generally, both alloys showed good hardness values attributed to the transition in the lattice structure from FCC to BCC, which contributes to the increment in hardness values. More so, the rapid solidification during laser additive manufacturing leads to excellent microhardness properties compared with alloys fabricated by conventional methods; arc melting [97]. The hardness properties of AlTiCrFeCoNi HEA make it favourable for wear resistant coating applications. Due to the AlCoCrFeNiCu alloy’s composition, the highest hardness values occurred at an increased laser power and scan speed while the AlTiCrFeCoNi occurred at a lower power and high scan speed as shown in Figure 14 (a) and (b).