Indentation-induced localized deformation and elastic strain partitioning in composites at submicron length scale
✍ Scribed by R.I. Barabash; H. Bei; Y.F. Gao; G.E. Ice
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 1009 KB
- Volume
- 58
- Category
- Article
- ISSN
- 1359-6454
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✦ Synopsis
Three-dimensional spatially resolved strains were mapped in a model NiAl/Mo composite after nanoindentation. The depth-dependent strain distributed in the two phases and partitioned across the composite interfaces is directly measured at submicron length scale using X-ray microdiffraction and compared with a detailed micromechanical stress analysis. It is shown that indentation-induced deformation in the composite material is distinct from deformation expected in a single-phase material. This difference arises in part from residual thermal strains in both phases of the composite in the as-grown state. Interplay between residual thermal strains and external mechanical strain results in a complex distribution of dilatational strain in the Mo fibers and NiAl matrix and is distinct in different locations within the indented area. Reversal of the strain sign (e.g., alternating tensile/compressive/tensile strain distribution) is observed in the NiAl matrix. Bending of the Mo fibers during indentation creates relatively large $1.5°misorientations between the different fibers and NiAl matrix. Compressive strain along the h0 0 1i direction reached À0.017 in the Mo fibers and À0.007 in the NiAl matrix.