Effect of aging on microstructure and wear resistance of Ti-55511/BN composite coating

ABSTRACT

In situ synthesized TiN and TiB reinforced metal matrix composite coating was fabricated on Ti-55511 by laser cladding with Ti-55511/BN powder mixture (2 wt-% BN). Results indicated that coating was mainly composed of TiB, dendrite TiN and α phase. The diameter of small-sized hollow tubular TiB was less than 400 nm, and the width of the other rod-shaped TiB was less than 1 μm. The flower-like structure formed during solidification consisted of TiN dendrite in centre and rod-shaped or hollow tubular TiB at edge. Coating had high hardness (540 HV) due to formation of TiB and TiN. After direct aging (600°C/5 h/AC), the hardness of coating and HAZ increased to 660 and 450 HV respectively because of nano-scaled α phase precipitation. In the friction and wear test, the weight loss of the coating was only 62% of that of substrate, which further reduced to 47% after aging.

KEYWORDS:

• Laser cladding
• titanium alloy
• coating
• microstructure
• wear

Acknowledgements

This work was supported by National Key R&D Program of China (2018YFB1105800 and 2018YFB2002000), National Science and Technology Major Project (2017-VII-0003-0096) and Beijing Municipal Science & Technology Program (Grant No. Z181100003318001).

Disclosure statement

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

Additional information

Funding

This work was supported by National Key R&D Program of China [2018YFB1105800 and 2018YFB2002000], National Science and Technology Major Project [2017-VII-0003-0096] and Beijing Municipal Science & Technology Program [grant number Z181100003318001].