Vacuum Plasma Spray Forming of Shape-Memory Alloy Components

MRi proposes to develop manufacturing NiTi and higher transition temperature NiTiPd SMA (shape memory alloys) processes based on vacuum plasma spray consolidation of prealloyed powders into near- net shapes. Shape-memory alloys (SMA's) have emerged as materials with unique thermal and mechanical properties could be used to reconfigure the shape change the angles of the rotor blades or for actuation and reconfigurability in aircraft aero-control surfaces.. MRi is proposing using vacuum plasma spray consolidation to eliminate many of the cast and wrought defects, while offering an opportunity to be able to shape difficult to form NiTi and NiTiPd alloys. In the proposed investigation NiTi and NiTiPd prealloyed powders would be fed into plasma jets that are operating in low pressure inert gas atmospheres where the heated powders are deposited onto mandrels that would shape the deposits. In Phase II, MRi would team with Boeing, the University of Washington and Plasma Processes Inc. to demonstrate the feasibility of the vacuum plasma spray process including post processing thermal mechanical treatments , to elicit optimum shape memory effects in the VPS formed NiTi and subsequently in the NiTiPd materials. Full materials characterization will be conducted including the determining Ms, Mf, As and Af transition temperatures and stress-strain vs. temperature behavior. In parallel to the analytical studies MRi will be teaming with Boeing to measure the engineering characteristics of the VPS formed NiTi and the NiTi materials, looking at longer term cycling ability and stability. Additionally, MRi will produce several tube nearly full scale actuator tube actuators for Boeing test and evaluation.