Electron Beam Surface Modification of Cobalt Chrome Molybdenum Alloy Formed by a Laminate Molding Method

Abstract:

We used electron beam irradiation on a laminate molded Co-Cr-Mo bulk alloy to reduce the surface roughness and increase hardness. The accelerating voltage and beam current were 40 kV and 0.5~5.0 mA, respectively. Irradiation time for each dot was 0.1 ms and the distance between dots (dot pitch) was either 0.2 or 0.4 mm, which corresponded to a scanning speed of 200 or 400 mm/s, respectively. The roughness value, Ra, decreased to 0.3~0.45 m for a beam current of 1 mA and a dot pitch of 0.02 mm. The coarse grains present in the base alloy were refined to sizes of less than 1m by rapid solidification. An increase in the Knoop hardness from 470 HK for the base metal to about 550 HK was achieved by this technique.

• Periodical: Materials Science Forum (Volumes 638-642)
• Pages: 2121-2126
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.638-642.2121
• Online since: January 2010
• Authors: Takekazu Nagae, Shigeki Kakiuchi, Kiyokazu Himi, Shogo Tomida, Emi Yamaguchi, Takashi Yoneda
• Keywords: Cobalt-Chrome-Molybdenum Alloy, Electron-Beam, Knoop Hardness, Laminate Molding, Rapid Solidification, Surface Roughness (SR)

References

[1] Joon Park and R.S. Lakes : Biomaterials An Introduction Third Edition (Springer, USA 2007).

[2] A. Chiba, K. Kumagai, N. Nomura and S. Miyakawa : Acta Materialia 55(2007) pp.1309-1318.

[3] T. Hanawa, K. Nakazawa, K. Kano, S. Hiromoto, Y. Suzuki and A. Chiba : Materials Trans. Vol. 46 No. 7(2005) pp.1593-1596.

DOI: 10.2320/matertrans.46.1593

[4] P. Petrov : Vacuum Vol. 48 No. 1 (1997)pp.49-50.

[5] T. Tauqir, H. Zaigham, F.H. Hashmi and A.Q. Khan : Journal of Mat. Sci. 32(1997)pp.465-468.

DOI: 10.1023/a:1018578005717

[6] A.B. Markov and V.P. Rotshtein : Nuclear Instruments and methods in physics research B 132(1997)pp.79-86.

[7] D. Dimitrov. M. Aprakova, S. Valkanov and P. Petrov : Vacuum, Vol. 49 No. 3 (1998) pp.239-246.

DOI: 10.1016/s0042-207x(97)00168-1

[8] Seong-Hun Choo, Sunghak Lee and Soon-Ju Kwon : Metallurgical and materials transactions A Vol. 30A (1999)pp.1211-1221.

[9] Japan Institute of Metals : Kinzoku Databook 4 th edition (Maruzen Japan 2004)p.16.

[10] P-F. Paradis, T. Ishikawa and N. Koike : High Temperatures-High Pressures, Vol. 37 (2008)pp.5-11.

[11] N. Nomura, M. Utsuhashi, M. Abe, T. Ono and A. Chiba : J. Japan Inst. Metals Vol. 70 No. 3 (2006) pp.281-286.

[12] R.D. Arnell : J. Phys. D: Appl. Phys. Vol. 7(1974) pp.1225-1232.