*6.2.6.1 Proposed solution*

The only way to fix the problem of delamination and cracks is by preventing them. It can be achieved by optimizing solidification. Preheating the printing environment and substrate can be a good solution as well. Avoid using combined material in the DED processes that might separate the layers between them when the dissimilar material has significant difference in the chemical reaction and solubility. Comprehensive study should be performed on the metals which are difficult to melt and solidify without cracks and delamination such as Inconel. Developing temperature map of the printed surface, that might help to optimize the preheating, can avoid cracking and delamination. The high cooling rate is also a cause of cracks and delamination. However, it is mentioned previously that it is a good solution to

avoid some defect such as heat accumulation. Therefore, an optimal cooling rate should be used to avoid and consider these defects.
