Comparative study of mechanical properties of pure nanocrystalline Ni and Ni-Tf nanocomposite

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2017-01, Vol.684, p.626-633
• Main Authors: Chatterjee, Arnomitra, Sharma, Garima, Varshney, Jalaj, Neogy, S., Singh, R.N.
• Format: Article
• Language: English
• Subjects: Activation volume; Comparative studies; Dispersion; Ductility; Loading rate; Mechanical properties; Nanocomposite; Nanocomposites; Nanocrystalline Ni; Nanoindentation; Nickel; Polytetrafluoroethylene; Strain rate; Strain rate sensitivity; Tensile test; Tensile tests; Tension tests; Ultimate tensile strength; Yield stress
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2016.12.052

Mechanical properties of nanocrystalline (nc) Nickel (Ni) and Ni-Teflon (Ni-Tf) nanocomposite has been studied in detail using nanoindentation and conventional tensile tests. Nanoindentation tests carried out at room temperature over a range of loading rate exhibited higher hardness for the nanocomposite as compared to the nc-Ni due to Tf dispersion. An increase in strain rate sensitivity (SRS) and decrease in activation volume of the nanocomposite as compared to nc-Ni was also observed. Tensile tests were carried out over a temperature regime of room temperature (RT) to 500°C. Tensile data also showed enhancement of yield stress and ultimate tensile strength up to 150°C. But from 200°C and above, Tf dispersion is unable to provide superior strength over nc-Ni as both the materials show almost similar strength. However, the ductility of the Ni-Tf nanocomposite was observed to be higher at all temperature compared to the pure nc-Ni. SRS was found to increase with temperature while SRS in nanocomposite had higher value below 200°C. The present study reveals that Ni-Tf nanocomposite possess better strength and ductility compared to nc-Ni up to 200°C.