Laser powder bed fusion of Al–10 wt% Ce alloys: microstructure and tensile property

The increasing potential for additive manufacturing technology continuously drives the need for printable materials, including novel aluminum alloys. Ce is considered an economically feasible addition that is beneficial to corrosion resistance and high temperature performance of aluminum alloys. In this study, a binary Al–10Ce alloy was additively manufactured by laser powder bed fusion (LPBF) using gas-atomized powders for the first time. Initial investigation was carried out to determine the optimal LPBF parameters for the Al–10Ce alloy, which was found using the laser power of 350 W and scan speed of 1400 mm/s. Alloy samples with nearly full density and outstanding printability were obtained. Room temperature tensile tests of the as-built Al–10Ce alloy yielded 222 ± 2 MPa in yield strength, 319 ± 1 MPa in tensile strength and 10.8 ± 0.1% in elongation. This is superior to the cast counterpart reported in the literature. A uniform microstructure was observed throughout the alloy, and it primarily consisted of extremely fine-scale eutectic Al and Al11Ce3 intermetallic ribbons, arranged in a skeleton pattern. This fine microstructure would have originated from the rapid cooling inherent to the LPBF process, and strongly suggests the presence of the Orowan strengthening mechanism. This study demonstrated that the binary Al–10Ce alloy is a promising base composition with good printability that brings new possibilities for future ternary and higher-order alloy design for LPBF.