1990 Volume 8 Issue 4 Pages 510-514
The influence of the reaction zone thickness in fiber-matrix reaction on the tensile strength of commercially pure titanium, Ti-6Al-4V and Ti-21V-4Al alloys matrix composites reinforced with silicon carbide fiber made by CVD method was investigated. The silicon carbide fiber is called SCS-6, which is provided for Ti matrix by AVCO CO, Ltd. And the effects of various kinds of additives on the growth rate of reaction zone were also examined using Ti-base binary alloys matrices.
The tensile strength of these composites decreased with the increase of the reaction zone due to heattreating reaction, but the strength was not reduced while the thickness of reaction zone was up to about 1μm. Concerning this fact, the fracture mechanism of the reaction zone was discussed based on the circumferential notch analysis proposed by Irwin.
The Ti-base binary alloys matrix composites containing Al, V, Me and Cr up to about 30 at%, and Zr and Sn up to about 10 at% could play the most important role in the mechanism responsible for the decrease of the growth rate of the reaction zone with the increase of the additives. This shows that the reaction could be controlled using such additives as mentioned above, which contributes to the stabilization of the composites under severe service conditions, comparing with the case of fibers coated with reaction inhibitors.