A microstructural study was conducted on 15 cobalt-chromium-nickel alloys of the basic composition 40 Co-30 Ni-30 Cr. The alloys were strengthened by the addition of tantalum and tantalum-rich regions were found at the interdendritic spaces. The increase in Ta concentration caused a decrease in the concentration of the β phase and an increase in the amounts of the a phase. Excessive amounts of Ta resulted in formation of the σ phase. The failure of the alloy occurred as a result of the interconnection of σ regions.
Get full access to this article
View all access options for this article.
References
1.
Mohammed, H. , and Asgar, K.: A New Dental Superalloy System: I. Theory and Alloy Design, J Dent Res52:136-144, 1973.
2.
Mohammed, H. , and Asgar, K.: A New Dental Superalloy System: II. Mechanical Properties, J Dent Res52 :145-150, 1973.
3.
Cochran, W.G. , and Cox, G.M.: Experimental Design, New York: Wiley and Sons, 1966.
4.
Fisher, R.A. : Statistical Methods for Research Workers, 10th ed, London: Oliver and Boyd, 1946.
5.
Sims, C.T.: A Contemporary View of Cobalt-Base Alloys, J Metals21:27-42, 1969.
6.
Johnson, R.S., JR.: Determinations of a Partial Room-Temperature Ternary Constitution Diagram in the As Cast Cr-Co-Ni System Utilizing a Factorial Experimental Design, PhD dissertation, University of Michigan, 1970.
