Plane stress fracture toughness of freestanding nanoscale thin films

• Published in: Thin solid films Vol. 516; no. 18; pp. 6444 - 6447
• Main Authors: Hosokawa, H., Desai, A.V., Haque, M.A.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 31-07-2008; Elsevier Science
• Subjects: Compact tension test; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Exact sciences and technology; Focused ion beam; Fracture toughness; Materials science; Mechanical and acoustical properties; Mechanical and acoustical properties of condensed matter; Mechanical properties of nanoscale materials; Methods of deposition of films and coatings; film growth and epitaxy; Micro-electro-mechanical systems; Physical properties of thin films, nonelectronic; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films; Thin films; Compact tension test; Micro-electro-mechanical systems; Focused ion beam; Fracture toughness; Scanning electron microscopy; Gold; Mechanical properties; Brittle material; Aluminium; Nanostructures; Dislocations; Ion beams; Nanometer scale; Stress effects; Sputter deposition; Microelectromechanical device
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2008.03.005

Fracture toughness values of notched thin films were measured in-situ in the scanning electron microscope using a micro-machined experimental setup. Freestanding specimens, 200–300 nm thick, 2 μm wide and about 10 μm long, were fabricated from extruded gold micro-wire and sputtered aluminum films. The obtained values, 0.45 MPa m
1
/
2 for gold and 0.51 MPa m
1
/
2 for aluminum are on the same order of those for brittle materials. Such reduction in fracture toughness is discussed in light of reduced dislocation activities in the severely work hardened gold and dislocation starved aluminum specimens.