WE Sem & Colloq
All dates for this event occur in the past.
"Effect of Heat Treatment on microstructure of additively manufactured Ni-based superalloys"
Colleen Hilla
Microstructure impacts the mechanical behavior of Ni-based superalloys. By leveraging unique thermal conditions of additive manufacturing, different microstructures can be explored for their effects on mechanical properties. A directionally solidified microstructure with a square/lattice cross section is seen in some laser powder bed (LPBF) builds. This study aims to determine the effect of that various solutionizing treatments have on the final part microstructure. The microstructure and texture of Rene 65 printed by LPBF were analyzed using EBSD and the precipitate structure was analyzed using backscattered electron imaging. The heat treatment temperature was varied including both supersolvus and subsolvus temperatures. The solutionizing time as well as the cooling rate were also varied to determine the effects on final microstructure before and after aging. For all three variables both the grain and precipitate size and structure were affected.
“Exploration and development of a conformable heat-sealing process for polymer films”
Flint Colvin
The most common method of sealing thermoplastic films is done with a constant temperature, hot metal tool. The rigidity of tooling can cause issues when forming a seal. Irregularities in material thickness, tooling parallelism, and deliberate transitions in film thicknesses combine with tool rigidity to cause non-uniform pressure. Localized areas with low pressure can have weak seals or no seal, both of which can be subject to leaks. A conformable tool or process would decrease or eliminate low pressure zones, even near film thickness transitions. In addition, a conformable process would necessitate less adhesive squeeze out, resulting in a stronger seal. During phase I of this project, potential tools/processes were brainstormed and analyzed. For phase II, the best options were selected for further exploration. Potential phase I tools and processes included: conductive elastomer composite tool, liquid metal tooling, metal powder tooling, complaint dielectric platen for radio frequency sealing (RF), compliant resistive heating elements, ultrasonic sealing with compliant anvil or horn, laser/IR heating with a compliant roller or sealing bladder. During phase II, prototypes of metal powder tooling and complaint resistive heating tooling will be built and tested. Currently, testing is being done on a resistively heated wire cloth/silicone rubber composite tool.