About this Abstract |
Meeting |
2021 TMS Annual Meeting & Exhibition
|
Symposium
|
Heterostructured and Gradient Materials (HGM IV): Tailoring Heterogeneity for Superior Properties
|
Presentation Title |
High Strength and Tensile Ductility in Bicrystalline Nickel Thin Films with Incoherent Twin Boundaries |
Author(s) |
Rohit Berlia, Jagannathan Rajagopalan |
On-Site Speaker (Planned) |
Jagannathan Rajagopalan |
Abstract Scope |
Freestanding metallic films typically show high strength but low strain hardening capacity, which leads to low failure strains (< 5%). Here, we report the mechanical behavior of bicrystalline Ni films that exhibit high strength and significant ductility. Ni films (200 nm - 2.5 μm thick) were deposited on Si (111) substrates with a 25 nm Ag buffer layer at room temperature using magnetron sputtering. TEM and EBSD characterization revealed that the films are composed of two (111) grain variants with an incoherent twin boundary at their interface. Freestanding samples of the films were co-fabricated with MEMS tensile stages and their uniaxial stress – strain response was measured at quasi-static strain rates. The experiments revealed flow stresses approaching 1 GPa and significant strain hardening, which resulted in uniform elongation >10% in the thickest films. Possible mechanisms for the high strength and relatively large ductility in these films will be discussed. |
Proceedings Inclusion? |
Planned: |
Keywords |
Mechanical Properties, Characterization, Copper / Nickel / Cobalt |