(Cu0.5Zr0.5)100-xAlx (x = 5, 6, 8) bulk metallic glasses (BMGs) were deformed in tension. Besides ductility up to 0.5%, the material shows work-hardening behaviour. Both effects are attributed to the deformation-induced precipitation of B2 CuZr nanocrystals and the formation of twins in the nanocrystals larger than 20 nm. The precipitation of the nanocrystals alters the stress field in the matrix and is expected to retard shear band propagation, which in turn allows stresses in the nanocrystals to rise. This stress build-up is more severe in the larger grains and might be responsible for the subsequent twinning. Both deformation-induced nanocrystallization and twinning consume energy and avoid crack formation and with it premature failure.
Bibliographical noteFunding Information:
The authors thank B. Bartusch, U. Wilke, S. Donath, M. Frey, and H. Schulze for technical assistance, and J. Das, H. Ehrenberg, D.C. Hofmann, H.P. Karnthaler, N. Mattern, S. Scudino, M. Stoica, T. Waitz, and M. Zehetbauer for stimulating discussions. Financial support provided by the Global Research Laboratory Program of the Korean Ministry of Education, Science and Technology is gratefully acknowledged. S.P. furthermore acknowledges financial support granted by the program “Promotionsförderung des Cusanuswerks”.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys