Finite Element Simulation and X-Ray Microdiffraction Study of Strain Partitioning in a Layered Nanocomposite

R I Barabash,S Koric,J Z Tischler,V Agarwal,I Jasiuk

doi:10.1155/2016/4351347

Abstract

The depth-dependent strain partitioning across the interfaces in the growth direction of the NiAl/Cr(Mo) nanocomposite between the Cr and NiAl lamellae was directly measured experimentally and simulated using a finite element method (FEM). Depth-resolved X-ray microdiffraction demonstrated that in the as-grown state both Cr and NiAl lamellae grow along the 111 direction with the formation of as-grown distinct residual ~0.16% compressive strains for Cr lamellae and ~0.05% tensile strains for NiAl lamellae. Three-dimensional simulations were carried out using an implicit FEM. First simulation was designed to study residual strains in the composite due to cooling resulting in formation of crystals. Strains in the growth direction were computed and compared to those obtained from the microdiffraction experiments. Second simulation was conducted to understand the combined strains resulting from cooling and mechanical indentation of the composite. Numerical results in the growth direction of crystal were compared to experimental results confirming the experimentally observed trends.

Highlights

Strain partitioning is the most important phenomenon responsible for unique properties of composites [1,2,3,4,5,6,7]
Nibased [3] and especially NiAl-based composites are the focus of current research because they can operate at high temperatures in corrosive environments [10,11,12,13,14,15,16,17]
They can be used for high temperature applications including structural components in energy conversion facilities, for example

Summary

Introduction

Strain partitioning is the most important phenomenon responsible for unique properties of composites [1,2,3,4,5,6,7]. Nibased [3] and especially NiAl-based composites are the focus of current research because they can operate at high temperatures (up to 1300∘C) in corrosive environments [10,11,12,13,14,15,16,17]. The mechanism of strain partitioning in these alloys and the role of interfaces in load transfer from one phase to another are still poorly understood. These open issues provided motivation for this study. The spherical shape of the indent was chosen in order to prevent the interplay between the specific shape of the indent with the crystal lattice anisotropy

Materials and Experimental Procedures

Results and Discussion

Cr top

Numerical Implementation and Computational Challenges

Conclusions