|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Ultrafine Grained Materials IX
||Sputter Deposited Nickel-Molybdenum-Tungsten Thin Films with High Strength and Ductility for Use in Metal MEMS Applications
||Gi-Dong Sim, K.Madhav Reddy, Gianna Valentino, Jessica A. Krogstad, Timothy P. Weihs, Kevin J. Hemker
|On-Site Speaker (Planned)
Development of metal MEMS alloys that possess enhanced mechanical and functional properties, dimensional stability, and the ability to be shaped on the microscale would greatly expand the design space for MEMS devices. Advanced metallic alloys are especially attractive in applications that require high density, electrical and thermal conductivity, strength, ductility and toughness. Here we report the mechanical behavior of sputter deposited Nickel(Ni)-Molybdenum(Mo)-Tungsten(W) thin films annealed at various temperatures. The as-deposited films resulted in a single-phase nanocrystalline solid solution and showed linear elastic response to a tensile strengths of ~3 GPa. Subsequent heat treatments resulted in grain growth, the nucleation of Mo-W precipitates and in some cases elastic-perfectly plastic behavior with strength greater than 1.2 GPa and approximately 10% tensile ductility. The brittle (ultra high strength) to ductile transition suggest that sputtering and subsequent heat treatment offers an attractive route for depositing metallic MEMS materials with tailorable mechanical properties.