Selective Laser Melting of Al0.3CoCrFeNi High-Entropy Alloy: Printability, Microstructure, and Mechanical Properties

Abstract

Al 0.3 CoCrFeNi high-entropy alloy (HEA) was additively manufactured by powder-bed selective laser melting (SLM) with emphasis on its microstructure and tensile properties. Al 0.3 CoCrFeNi showed excellent printability, enabling fabrication of fully dense products. The microstructure of the SLM as-built HEA consisted of a single-phase disordered face-centered cubic solid solution with fine columnar grains elongated along the build direction. The characteristic features of the as-built microstructure were a <110> fiber texture aligned toward the build direction and a large dislocation density. As a consequence, printed Al 0.3 CoCrFeNi HEA exhibited superior tensile strength in comparison with as-cast or wrought counterparts.

A Review of the Selective Laser Melting Lattice Structures and Their Numerical Models

“…Peyrouzet et al found that the an as‐printed SLM Al 0.3 CoCrFeNi HEA exhibits superior tensile strength (896 MPa) with decent ductility (≈29%) in comparison with the same alloy in as‐cast or wrought state. [ 110 ] Lin et al investigated the effect of the annealing temperature on the microstructure and mechanical properties of an SLM FeCoCrNi HEA. [ 102 ] The authors found that increasing the annealing temperature leads to a gradual decrease in yield strength and an increase in plasticity.…”

Enhanced tensile yield strength in laser additively manufactured Al0.3CoCrFeNi high entropy alloy

“…The av erage dislocation density measured from BFTEM images, recorded from at least three distinct regions, was ~5 × 10 13 /m 2 . This value can be considered to lie in between the dislocation density of a fully recrystal lized/annealed metallic alloy (~10 11 /m 2 [36] ) and the typical disloca tion density reported in case of selectively laser melted (SLM) alloy sam ples (~10 14 /m 2 [37] ) . An additional factor that can result in a higher YS is the presence of fine scale cells or sub grain structures within the primary grains [38] .…”

Powder metallurgy of Al0.1CoCrFeNi high-entropy alloy

“…For engineering alloys, the yield strength can be dictated by the strengthening factors like intrinsic lattice friction (σ LF ), solid solution strengthening (σ SSS ), grain boundary strengthening/Hall-Petch strengthening (σ HP ), dislocation strengthening (σ dislo ), and particle dispersion strengthening (σ disp ). The yield strength of the alloy can be predicted by using the formula given in the following equation [75,76,77,78,79]:…”

“…The remaining strength contributing factors (σ HP , σ dislo , and σ displ ) can be evaluated from Eqs. (3)-(5) [76].…”