Deformation behavior of multilayered NiFe with bimodal grain size distribution at room and elevated temperature

Abstract

We describe a study of the temperature dependent deformation behavior of a multilayered NiFe-60wt%Fe alloy with a layer thickness of 5 μm fabricated by electrodeposition. The structure of adjacent layers alternates between a nanocrystalline and a coarse grained. Uniaxial tensile tests at temperature between 20˚C and 400˚C and strain rate of 10-4-10-2 were used to determine the mechanical behavior. Microstructure observations via transmission electron microscopy and fractography were performed to provide insight into the underlying deformation mechanism. The mechanical behavior is discussed in the context of the bimodal microstructure of multilayered samples and the contribution of each sub-layer to strength and ductility. The results reveal that even at higher temperatures the nanocrystalline layer determines the mechanical performance of multilayered materials.

Tribological and Corrosion Behavior of St37 Steel by Electrochemically Deposited Ni-Fe/Al 2 O 3 Coating

“…In this method, two or more alternative layers that have different compositions and properties are used [7]. Compared to the monolithic coating method, due to the high hardness of the layers and graded microstructures, the surface properties such as mechanical, electrochemical, optical and oxidation resistance are signi cantly increased [8] [9] [10]. Also, composite multilayer coatings not only have lower shear stress but also show a good ability to prevent crack growth, which increases the lifetime properties of the part [11] [12].…”

Size effects in strengthening of NiCo multilayers with modulated microstructures

“…In this regard, microstructure-modulated MLs add crystal size as a new dimension to scaling relationships in MLs. Early studies on the mechanical properties of microstructure-modulated MLs are reported by Chan et al [21], Lavernia and coworkers [22][23][24], and Daly et al [25] for architectures comprised of alternating nanocrystalline (NC) and coarsegrained (CG) layers. While these initial studies have revealed the mechanical behavior of ML with modulated microstructures, a broader understanding of the interplay between crystal size and layer thickness (i.e., multiple independently controlled size effects) is currently lacking.…”