| Abstract Scope |
With the industrial commercialization of fusion energy and changing defense needs, there is increased demand for refractory metal components. These materials are difficult to machine, have a high base material cost, and are vulnerable to supply chain disruptions. This has poised additive manufacturing of these components to be highly desirable. However, due to a high ductile to brittle transition temperature seen in some refactory metals, such as W, there are significant printability concerns as well. As new materials are developed for various applications, data is needed to determine if they are a good candidate for additive manufacturing. The identified need is to develop a process that can be used to rapidly quantify alloy printability to compare with known materials. Short thin wall structures of binary and ternary alloys containg W, Ta, Re, Mo, Nb, and Ti were printed using directed energy deposition. Through previous work, similar materials have been shown to be most sensitive to laser power and powder feed rate. Five print paramter sets were used for each alloy varying power and feed rate, looking +/- 20% of the predicited ideal parameters. Modeling and early results were used to identify the shift needed to appropriately bound each alloy. Samples were analyzed for defect quantity, an additional factor was given for interconnected pores or large cracks, proportional to the crack length. EDS was completed to verify alloy composition. Loss of Ti is common for these alloys as the boiling point is near or below the melting point for W and Ta. Alloys were given a printability value and ranked based on relative printability. This process can be used to evaluate novel refractory alloys for printability given know values for common alloys. |