Superthermostability of nanoscale TIC-reinforced copper alloys manufactured by a two-step ball-milling process

Abstract

A Cu-TiC alloy, with nanoscale TiC particles highly dispersed in the submicron-grained Cu matrix, was manufactured by a self-developed two-step ball-milling process on Cu, Ti and C powders. The thermostability of the composite was evaluated by high-temperature isothermal annealing treatments, with temperatures ranging from 727 to 1273 K. The semicoherent nanoscale TiC particles with Cu matrix, mainly located along the grain boundaries, were found to exhibit the promising trait of blocking grain boundary migrations, which leads to a super-stabilized microstructures up to approximately the melting point of copper (1223 K). Furthermore, the Cu-TiC alloys after annealing at 1323 K showed a slight decrease in Vickers hardness as well as the duplex microstructure due to selective grain growth, which were discussed in terms of hardness contributions from various mechanisms.

Keywords:

• Ultrafine-grained (UFG) microstructure
• ball-milling process
• thermal stability
• particle pinning

Acknowledgements

The authors gratefully acknowledge the technical support received from Yukiti Imoto and Yuya Tanaka in Technical Center, Koichi Harata and Issei Narita in Cooperative Research and Development Center for Advanced Materials, IMR, Tohoku University.

Disclosure statement

No potential conflict of interest was reported by the authors.