Improving the microstructure and mechanical properties of laser powder bed fusion-fabricated tantalum by high laser energy density

•Unalloyed Tantalum was processed successfully by LPBF with high laser power (600 W).•The convert from columnar grain to equiaxed grain was obtained by high laser power.•A high-density sample with good mechanical properties was fabricated. The effect of laser energy density on the microstructural evolution and the mechanical properties, including tensile property and nanoindentation creep behavior of Ta parts were investigated. A high laser power strategy (600 W) was used to obtain Ta part with high density. The microstructure of Ta fabricated with 200 W comprised columnar grains with strong 〈111〉 texture, while equiaxed grains with random orientation were found in Ta fabricated with 600 W. The elongation to failure of the specimen fabricated at 600 W was higher than that of the specimen fabricated at 200 W, which stemmed from pore elimination and equiaxed grains. Nanoindentation creep results showed that the movement of dislocations was the main creep mechanism and the influence of laser energy density was discussed.