Properties of sputter deposited Ni-base superalloys for microelectromechanical systems

• Published in: Thin solid films 2014-05, Vol.558, p.20-23
• Main Authors: Burns, Devin E., Zhang, Yong, Weihs, Timothy P., Hemker, Kevin J.
• Format: Article
• Language: English
• Subjects: Aging; Alloy 718; Applied sciences; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Ductility; Electronics; Exact sciences and technology; Grain boundaries; High temperature microelectromechanical systems; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Micro- and nanoelectromechanical devices (mems/nems); Nanoscale materials and structures: fabrication and characterization; Nickel base alloys; Other topics in nanoscale materials and structures; Physics; Precipitation; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solid solutions; Sputtering; Structure and morphology; thickness; Superalloy; Superalloys; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Tensile strength; Tension test; Thin film structure and morphology; Thin films
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2014.02.051

Nickel-base superalloy 718 films have been sputter deposited to thicknesses of 20μm. These as-deposited films were single-phase nanocrystalline solid solutions, which possessed tensile strengths of 1GPa but negligible ductility. Standard 718 aging heat treatments resulted in modest grain growth, atypical precipitation behavior, significant ductility, and impressive strengths at both ambient (2GPa at 25°C) and elevated (750MPa at 700°C) temperatures. The density of grain boundaries was shown to have a dramatic effect on the precipitation pathways of this alloy. •Exceptional room temperature strength (2GPa) and ductility after aging•Sputtered superalloy had a similar composition as the target.•Film was essentially quenched from the vapor forming a solid solution.•Heat treatment resulted in unique precipitation pathways.•Small grain size contributed to mechanical properties and precipitation.