In the present investigation, Cu47Ti33Ni6Sn2Si1 (numbers indicate at.%) bulk metallic glass (BMG), fabricated by injection casting has been used for indentation experiments. Microindentation and nanoindentation tests were conducted to study the indentation responses of this material. The nanohardness and the Young's modulus were calculated following the standard procedure in literature. Around the indent, shear bands can be clearly observed under scanning electron microscopy examination. Atomic-force microscopy shows the pile of the material in a step-wise manner. The thinned sample near the indent shows the evolution of nanocrystals (∼20-30 nm) by transmission electron microscopy. During nanoindentation (in single- and multi-indent mode) experiments, the load-displacement P-h curves show displacement bursts, which are also known as pop-ins or serrations. The total displacement during indentation can be accounted for by sum total effect of the individual displacement of all the displacement-bursts observed in the P-h curve. Thus the plastic deformation of this glassy material appears to proceed in a discrete manner unlike ductile metallic alloys.
Bibliographical noteFunding Information:
The authors would like to thank Prof. S. Ranganathan, Prof. S. Lele and Prof. K. Chattopadhyay for useful discussions and Mrs. M. Reibold for her help in TEM investigation. One of the author (NKM) would like to thank Alexander von Humboldt Foundation, Germany for Research Fellowship during which a part of the work was completed. Partial support from Department of Science and Technology, India is gratefully acknowledged.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering