Mechanical testing of nanotwinned alloys
October 1-6, 2017
There has been much interest recently in nanotwinned metals due to their potential for simultaneous high strength and ductility. By introducing alloying elements, one can modify the stacking fault energy of the material, allowing for the synthesis of fully twinned structures with controlled microstructures. In this study, fully nanotwinned Cu-based binary alloys and Inconel 600 were synthesized by magnetron sputtering with stacking fault energies ranging from 6 to 60 mJ/m2, mean twin thicknesses ranging from 4 to 22 nm, and mean grain sizes ranging from 80 to 260 nm. Tensile and tension-tension fatigue behavior of these materials was determined with a custom-built small-scale tensile tester utilizing DIC to generate in-situ strain maps. The effects of varying microstructure are examined for different alloy systems in order to understand the effect of alloying elements in the mechanical behavior. The samples displayed yield strengths ranging from 830 to 1340 MPa for the Cu-based alloys and up to 2400 MPa for the Inconel 600, varying with both alloy content and microstructural parameters. Nanoindentation tests were also used to evaluate the deformation behavior for dual microstructures of twinned and non-twinned grains in order to identify optimum ductility.
Andrea M. Hodge and Nathan Heckman, "Mechanical testing of nanotwinned alloys" in "Nanomechanical Testing in Materials Research and Development VI", Karsten Durst, Technical University of Darmstadt, Germany Eds, ECI Symposium Series, (2017). http://dc.engconfintl.org/nanomechtest_vi/100