Influence of Deposition Strategy on Heat Input, Microstructure, and Mechanical Performance of Wire Arc Directed Energy Deposition Inconel 625

Cold metal transfer-based wire arc directed energy deposition (DED) offers the advantages of high forming efficiency and the capability to fabricate large and complex structural parts. However, the microstructure and mechanical performance of the deposited parts are largely dependent on the thermal history. Two deposition strategies (reciprocating and cross-deposition) were used to prepare Inconel 625 samples to assess their impact on heat accumulation, microstructure, and mechanical properties. The results show that with increasing build height, both samples experienced heat accumulation, resulting in a larger melt pool. The columnar crystals grow epitaxial in the reciprocating deposition, while equiaxed grains were formed during cross-deposition and smaller grain spacing. The Laves phase is more prominent in the reciprocating deposition due to the slower cooling rate. The cross-deposition samples exhibited superior mechanical properties, with TS of 749 MPa, YS of 615 MPa, and EL of 27% significantly better than the reciprocating deposition samples. In addition, the microhardness of cross-deposition was 8.85% higher. These findings highlight the advantages of cross-deposition for improving thermal management and optimizing mechanical properties in the wa-DED process, making it a more effective strategy for producing high-performance components.