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It is of great significance to explore the chemical compositions, which have not been hitherto examined for their suitability for additive manufacturing (AM), so as to broaden AM's material library. Since solidification cracking is a major impediment in AM of alloys, especially high entropy alloys (HEAs), a detailed study on the cracking issue during AM is imperative. Keeping this in mind, a customized laser powder bed fusion (LPBF) setup is utilized to fabricate a compositionally graded AlxCoCrFeNi (x = 0.04–0.75) HEA, using the equiatomic AlCoCrFeNi and CoCrFeNi powders as feedstock, to examine the compositional range that enables crack-free fabrication. Experimental results show that when x ≤ 0.7, crack-free fabrication is possible. This compositional range exceeds the threshold reported in the recent literature. Microstructural characterization reveals a constant dual phase structure throughout the gradient, which is induced by the chemical segregation. Further analysis shows that both utilizing AlCoCrFeNi powder as Al source and the segregation contribute to the enhanced printability. The results suggest that the dual phase structure introduced by chemical segregation can effectively inhibit the initiation and propagation of hot tearing problem in metal additive manufacturing. Agency for Science, Technology and Research (A*STAR) Published version The authors acknowledge the financial support of the National Natural Science Foundation of China (No.: 52171026). The work at Nanyang Technological University and Institute of Materials Research and Engineering was supported by Agency for Science, Technology and Research (A*STAR) of Singapore via the Structural Metal Alloys Programme (No. A18B1b0061).

A comparative study was conducted by using solution combustion synthesis with three different doping routes (liquid−liquid (WL10), liquid−solid (WLNO) and solid−solid (WLO)) to produce nanoscale powders and further fabricate the ultrafine-grained W−1.0wt.%La2O3 alloys by pressureless sintering. Compared with pure tungsten, W−1.0wt.%La2O3 alloys exhibit ultrafine grains and excellent mechanical properties. After sintering, the average grain size of the WLO sample is larger than that of WL10 and WLNO samples; the microhardness values of WL10 and WLNO samples are similar but larger than the value of WLO sample. The optimized La2O3 particles are obtained in the WL10 sample after sintering at 1500 °C with the minimum mean size by comparing with WLNO and WLO samples, which are uniformly distributed either at grain boundaries or in the grain interior with the sizes of (57±29.7) and (27±13.1) nm, respectively. This study exhibits ultrafine microstructure and outperforming mechanical properties of the W−1.0wt.%La2O3 alloy via the liquid−liquid doping route, as compared with conventionally-manufactured tungsten materials.