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3D x-ray microprobe investigation of local dislocation densities and elastic strain gradients in a NiAl-Mo composite and exposed Mo micropillars as a function of prestrain*

Published online by Cambridge University Press:  31 January 2011

Rozaliya I. Barabash ,
Hongbin Bei ,
Yanfei Gao ,
Gene E. Ice  and
Easo P. George
Rozaliya I. Barabash*
Affiliation:
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831; and Materials Science and Engineering Department, University of Tennessee, Knoxville, Tennessee 37996
Hongbin Bei*
Affiliation:
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
Yanfei Gao
Affiliation:
Materials Science and Engineering Department, University of Tennessee, Knoxville, Tennessee 37996; and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
Gene E. Ice
Affiliation:
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
Easo P. George
Affiliation:
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831; and Materials Science and Engineering Department, University of Tennessee, Knoxville, Tennessee 37996
*
a)Address all correspondence to this author. e-mail:Barabashr@ornl.gov
b)Address all correspondence to this author. e-mail: Beih@ornl.gov
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Abstract

3D spatially-resolved polychromatic microdiffraction was used to nondestructively obtain depth-dependent elastic strain gradients and dislocation densities in the constituent phases of a directionally solidified NiAl–Mo eutectic composite consisting of ∼500–800 nm Mo fibers in a NiAl matrix. Measurements were made before and after the composite was compressed by 5% and 11%. The Mo fibers were analyzed both in their embedded state and after the matrix was etched to expose them as pillars. In the as-grown composite, due to differential thermal contraction during cooldown, the Mo phase is under compression and the NiAl phase is in tension. After the prestrains, the situation is reversed with the Mo phase in tension and NiAl matrix in compression. This result can be explained by taking into account the mismatch in yield strains of the constituent phases and the elastic constraints during unloading. The dislocation density in both the Mo and NiAl phases is found to increase after prestraining. Within experimental uncertainty there is little discernible difference in the total dislocation densities in the Mo phase of the 5% and 11% prestrained specimens. However, the density of the geometrically necessary dislocations and the deviatoric strain gradients increase with increasing prestrain in both the Mo and NiAl phases.

Type
Outstanding Symposium Paper
Information
Journal of Materials Research , Volume 25 , Issue 2 , February 2010 , pp. 199 - 206
Copyright
Copyright © Materials Research Society 2010

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Footnotes

*

This paper was selected as an Outstanding Symposium Paper for the 2008 MRS Fall Meeting, Symposium EE Proceedings, Vol. 1137E. To maintain JMR’s rigorous, unbiased peer review standards, the JMR Principal Editor and reviewers were not made aware of the paper’s designation as Outstanding Symposium Paper.

References

REFERENCES

1.Uchic, M.D., Dimiduk, D.M., Florando, J.N., Nix, W.D.Exploring specimen size effects in plastic deformation of Ni3(Al,Ta)Defect Properties and Related Phenomena in Intermetallic Alloys edited by E.P. George H. Inui M.J. Mills and G. Eggeler (Mater. Res. Soc. Symp. Proc. 753, Warrendale, PA 2003)27Google Scholar
2.Uchic, M.D., Dimiduk, D.M., Florando, J.N., Nix, W.D.Sample dimensions influence strength and crystal plasticity. Science 305, 986 (2004)CrossRefGoogle ScholarPubMed
3.Dimiduk, D.M., Uchic, M.D., Parthasarathy, T.A.Size-affected single-slip behavior of pure nickel microcrystals. Acta Mater. 53, 4065 (2005)CrossRefGoogle Scholar
4.Greer, J.R., Nix, W.D.Nanoscale gold pillars strengthened through dislocation starvation. Phys. Rev. B 73, 255410 (2006)CrossRefGoogle Scholar
5.Volkert, C.A., Lilleodden, E.T.Size effects in the deformation of sub-micron Au columns. Philos. Mag. 86, 5567 (2006)Google Scholar
6.Kiener, D., Motz, C., Schoberl, T., Jenko, M., Dehm, G.Determination of mechanical properties of copper at the micron scale. Adv. Eng. Mater. 8, 1119 (2006)CrossRefGoogle Scholar
7.Shan, Z.W., Mishra, R.K., Syed Asif, S.A., Warren, O.L., Minor, A.M.Mechanical annealing and source-limited deformation in submicrometre-diameter Ni crystals. Nat. Mater. 7, 115 (2007)CrossRefGoogle ScholarPubMed
8.Bei, H., George, E.P.Microstructures and mechanical properties of a directionally solidified NiAl-Mo eutectic alloy. Acta Mater. 53, 69 (2005)CrossRefGoogle Scholar
9.Bei, H., Shim, S., George, E.P., Miller, M.K., Herbert, E.G., Pharr, G.M.Compressive strengths of molybdenum alloy micro-pillars prepared using a new technique. Scr. Mater. 57, 397 (2007)CrossRefGoogle Scholar
10.Bei, H., Shim, S., Pharr, G.M., George, E.P.Effects of prestrain on the compressive stress-strain response of Mo-alloy single-crystal micropillars. Acta Mater. 56, 4762 (2008)CrossRefGoogle Scholar
11.Bei, H., Gao, Y.F., Shim, S., George, E.P., Pharr, G.M.Strength differences arising from homogeneous versus heterogeneous dislocation nucleation. Phys. Rev. B 77, 060103(R) (2008)Google Scholar
12.Brickmann, S., Kim, J-Y., Greer, J.R.Fundamental differences in mechanical behavior between two types of crystals at the nanoscale. Phys. Rev. Lett. 100, 155502 (2008)CrossRefGoogle Scholar
13.Shim, S., Bei, H., Miller, M.K., Pharr, G.M., George, E.P.Effects of focused-ion-beam milling on the compressive behavior of directionally solidified micropillars and the nanoindentation response of an electropolished surface. Acta Mater. 57, 503 (2009)Google Scholar
14.Thompson, K., Lawrence, D., Larson, D.J., Olson, J.D., Kelly, T.F., Gorman, B.In situ site-specific specimen preparation for atom probe tomography. Ultramicroscopy 107, 131 (2007)Google Scholar
15.Mayer, J., Giannuzzi, L.A., Kamino, T., Michael, J.TEM sample preparation and FIB-induced damage. MRS Bull. 32, 400 (2007)CrossRefGoogle Scholar
16.Kiener, D., Motz, C., Rester, M., Jenko, M., Dehm, G.Ga+ ion beam damage during focused ion beam preparation of Cu samples. Mater. Sci. Eng., A 459, 262 (2007)Google Scholar
17.Norfleet, D.M., Dimiduk, D.M., Polasik, S.J., Uchic, M.D., Mills, M.J.Dislocation structures and their relationship to strength in deformed nickel microcrystals. Acta Mater. 56, 2988 (2008)Google Scholar
18.Maass, R., Grolimund, D., Van Petegem, S., Willimann, M., Jensen, M., Van Swygenhoven, H.Defect structure in micropillars using x-ray microdiffraction. Appl. Phys. Lett. 89, 151905 (2006)Google Scholar
19.Maass, R., Van Petegem, S., Van Swygenhoven, H., Derlet, P.M., Volkert, C.A., Grolimund, D.Time-resolved Laue diffraction of deforming micropillars. Phys. Rev. Lett. 99, 145505 (2007)CrossRefGoogle ScholarPubMed
20.Bei, H., Barabash, R.I., Ice, G.E., Liu, W., Tischler, J., George, E.P.Spatially resolved strain measurements in Mo-alloy micropillars by differential aperture x-ray microscopy. Appl. Phys. Lett. 93, 071904 (2008)CrossRefGoogle Scholar
21.Larson, B.C., Yang, W., Ice, G.E., Budai, J.D., Tischler, J.Z.Three-dimensional x-ray structural microscopy with submicron resolution. Nature 415, 887 (2002)Google Scholar
22.Bei, H., George, E.P., Brown, D.W., Pharr, G.M., Choo, H., Porter, W.D., Bourke, M.A.M.Thermal-expansion behavior of a directionally solidified NiAl-Mo composite investigated by neutron diffraction and dilatometry. J. Appl. Phys. 97, 123503 (2005)Google Scholar
23.Misra, A., Wu, Z.L., Kush, M.T., Gibala, R.Deformation and fracture behavior of directionally solidified NiAl-Mo and NiAl-Mo(Re) eutectic composites. Philos. Mag. 78, 533 (1998)Google Scholar
24.Ice, G.E., Barabash, R.I.White beam microdiffraction and dislocations gradientsDislocations in Solids Vol. 13, (2007) 500Google Scholar
25.Barabash, R.I., Ice, G.E., Liu, W., Barabash, O.M.Polychromatic microdiffraction characterization of defect gradients in severely-deformed materials. Micron 40, 28 (2009)CrossRefGoogle ScholarPubMed
26.Barabash, R.I., Gao, Y., Sun, Y., Lee, S.Y., Choo, H., Liaw, P., Brown, D., Ice, G.Neutron and x-ray diffraction studies and cohesive interface model of the fatigue crack deformation behavior. Philos. Mag. Lett. 88, 553 (2008)Google Scholar
27.Miracle, D.B., Darolia, R.NiAl and its alloysIntermetallic Compounds: Principles and Practice Vol. 2 edited by J.H. Westbrook and R.L. Fleischer (John Wiley & Sons, New York 1995)5372Google Scholar
28.Lee, S., Han, S.M., Nix, W.D.Uniaxial compression of fcc Au nanopillars on an MgO substrate: The effects of prestraining and annealing. Acta Mater. 57, 4404 (2009)CrossRefGoogle Scholar