We investigated the effect of geometrically constrained stress-strain conditions on the formation of nanotwins in -brass phase reinforced Ni59Zr20 Ti16 Si2 Sn3 metallic glass (MG) matrix deformed under macroscopic uniaxial compression. The specific geometrically constrained conditions in the samples lead to a deviation from a simple uniaxial state to a multi-axial stress state, for which nanocrystallization in the MG matrix together with nanoscale twinning of the brass reinforcement is observed in localized regions during plastic flow. The nanocrystals in the MG matrix and the appearance of the twinned structure in the reinforcements indicate that the strain energy is highly confined and the local stress reaches a very high level upon yielding. Both the effective distribution of reinforcements on the strain enhancement of composite and the effects of the complicated stress states on the development of nanotwins in the second-phase brass particles are discussed.
Bibliographical noteFunding Information:
This work was supported by the US Department of Energy under Contract No. DE-AC02-07CH11358 through the Cooperative Research and Development Agreement (AL-C-2012-04) between Ames Laboratory and KITECH. Work by RTO was supported by Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE-AC02-07CH11358, and FS thanks support from the National Science Foundation CAREER program (grant no. DMR-0747658). This work also supported by the Global Research Laboratory Program of the Korean Ministry of Education, Science and Technology.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics