Abstrakt
Bulk Nb-Ta-Ti-Zr refractory complex concentrated alloy (RCCA) was prepared by additive manufacturing method of directed energy deposition (DED) from an equiatomic mixture of elemental powders. Using elemental powders instead of pre-alloyed powder is beneficial in terms of costs and variability of chemical composition.
However, it is more demanding for optimization of deposition parameters. Variation of scanning velocity was used to study the effect of different heat inputs.
It was found that a decreasing scanning velocity effectively decreases the number of undissolved Nb/Ta particles present in the microstructure. Moreover, employing of the platform preheating to 500 degrees C during deposition resulted in the best microstructure homogeneity among the studied asdeposited samples.
Finally, homogenization annealing 1400 degrees C/24 h was performed. Despite the Thermo-Calc prediction of complete Ta particles dissolution, they remained still present in the material.
Reasonable microstructure homogeneity of RCCA produced from elemental powders must be achieved already by optimization of deposition parameters while the homogenization annealing is not feasible for heterogeneities in the scale of powder particles size.