Stable nanocrystalline structure attainment and strength enhancement of Cu base alloy using bi-modal distributed tungsten dispersoids

ABSTRACT

In this study, an experimental and atomic-scale simulation-based investigation has been performed to investigate the possible stability of the nano-crystalline structure and thereby considerable strength at a higher temperature in the case of synthesised Cu alloy along with logical understanding. Dispersions of high melting BCC metal (1 at% W) in nanostructured Cu is achieved using conveniently scalable cryomilling followed by hot pressing (at 550 °C). The thermal stability (till 800 °C) of grain size in synthesised nano-crystalline Cu alloy has been examined through X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The nano-sized W particles dispersed at the Cu matrix grain boundaries, restricting grain growth by Zener pinning even after annealing was carried out at 800 °C. The hot-pressed pellets of nanocrystalline Cu₉₉W₁ alloy with a nearly uniform distribution of W particles have exhibited higher hardness than pure Cu and increased in strength and strain to failure up to 10% and 46%, respectively. The improvement in mechanical properties is further rationalised by the Molecular Dynamics (MD) based simulation findings.

KEYWORDS:

• Nanocrystalline cu
• mechanical properties
• grain growth
• electron microscopy
• Molecular dynamics simulation

Acknowledgment

The corresponding author expresses his sincere gratitude to Prof. Carl C. Koch for access to the experimental facility in his laboratory at NCSU, Raleigh, USA. The authors gratefully acknowledge National Facility for Atom Probe Tomography (NFAPT) at IIT Madras, funded by DST for carrying out APT studies

Disclosure statement

No potential conflict of interest was reported by the author(s).