The objective of this project is to establish a scientific methodology for the reuse and recycling of tungsten-rhenium refractory alloy powder for additive manufacturing (AM). In pursuit of this goal, the primary research objective of this project is to develop a laser and electron-beam powder bed additive manufacturing process of the W-24Re alloy, develop powder reconditioning (deoxidation) technology via plasma spheroidization process, and investigate the properties and performance of additively manufactured W-24Re components produced using both virgin and recycled powders.
Many high temperature components such as turbine blades, rocket nozzles, and high-temperature heat exchangers are highly complex shapes that are very expensive to produce due to extensive machining. Moreover, the buy-to-fly ratio for complex refractory alloy components is very high, which makes W-24Re complex components very expensive due to scrap material removed in the manufacturing process. To overcome these challenges, here the project team plans to develop powder bed additive manufacturing processes of W-24Re alloy and develop a powder reconditioning technology for recycling and reuse of powders in additive manufacturing. In pursuit of this goal, the project is subdivided into the following five research aims, 1) Develop laser powder bed fusion and electron-beam powder bed fusion additive manufacturing processes of W-24Re alloy, 2) Investigate the microstructure and mechanical properties of additively manufactured W-24Re coupons produced with virgin powder, 3) Develop powder reconditioning (deoxidation) technology based on plasma spheroidization process, 4) Investigate the microstructure and mechanical properties of additively manufactured W-24Re coupons produced with recycled powder, and 5) Investigate the performance of additively manufactured rocket nozzle produced with both virgin and recycled powder via hot fire test.
The developed technology from this project will bring the following technical benefits for the reuse and recycling of W-Re refractory alloy powder and other refractory metal/alloy scrap. Tons of out-of-spec or unmelted powder generated by the current powder bed AM process can be re-processed to meet virgin powder’s qualification for making high-quality AM products and reduce the overall AM cost. In addition to lowering the cost of the AM process, this recycling capability will also mitigate the U.S. dependence on international suppliers for critical metals such as Rhenium. This research can be applied to the powder processing technology of refractory metal scrap generated from gas turbines, rocket nozzles, high temperature heat exchangers, and nuclear power plants to make new AM powder. The development and optimization of this technology will provide an environmentally friendly manner for mitigating environmental risks and remediation costs of both metal powder waste and scrap at Department of Defense and Department of Energy complexes across the U.S.