Researchers at the National Institute of Standards and Technology (NIST) have developed an elliptical laser stirring method for metal additive manufacturing, addressing the challenge of uniformly mixing different metals at the atomic level during solidification in high-entropy alloy production. High-entropy alloys, composed of roughly equal proportions of multiple metals, offer performance advantages at high temperatures, but the significant differences in density, melting points, and surface tension of different metals cause them to separate into discrete regions during cooling. The research team replaced the traditional linear scanning pattern with an elliptical trajectory in laser powder bed fusion (LPBF) to actively stir the melt pool. Since commercial 3D printer software cannot generate elliptical scanning paths, the team wrote control software from scratch, allowing existing equipment to use the method via reprogramming without new hardware. They successfully printed a "sandwich" structure comprising Ti6Al4V, RHEA-19 high-entropy alloy, and Ti6Al4V, with a total thickness of 2.4 mm and each of the three layers measuring 0.8 mm. This method also enables on-demand alloying within the printer and even continuous variation of alloy composition within the same part.