Continuous Binder-Powder Coating for the Production of Ti/SiC/C Composites

Abstract

Continuous Binder-Powder Coating (CBPC) is a new fabrication route for the titanium metal matrix composites reinforced with continuous SiC filaments. Based on powder-cloth process, this alternative fabrication route is characterised, analysed and application viability is discussed considering the other related routes. In addition, effects of the pressure and temperature on the Ti/SiC/C composites were considered for matrix consolidation. Results have shown that the titanium matrix composites processed by Continuous Binder-Powder Coating present, simultaneously, good matrix densification, consolidation and also a weak interaction between matrix and fibers, when the hot pressing is performed under 150 MPa at temperature below β-transus. Most important characteristics of the CBPC process and its application viability are reported, in this paper.

Matrix consolidation mechanism in 1D-Ti/SiC/C composites produced by continuous binder-powder coating

“…In CBPC process, results showed that both pressure and temperature are important parameters for matrix consolidation, contrary to the fiber-foil-fiber process in which the temperature has a less important role, as compared with the pressure [1][2] . Despite of the differences between binder-powder coating and fiber-foil-fiber manufacturing conditions, the final results concerning the matrix consolidation are in agreements 1,2,7,[12][13][14] . For all temperatures between 700 and 800 °C performed in CBPC process, both the plastic deformation and the diffusion bonding (as consequence) are weak and insufficient for porosity elimination, if a pressure of 100 MPa is applied.…”

“…For instance, fiber breakage was systematically induced by pressure application at rates higher than 5 MPa/min, even though the final pressure is smaller than 180 MPa. This effect can be explained by considering that in high rates of pressure increase, the isostatic compressive component of the stress field is insufficient, when compared to the stresses induced by sharp points of Ti-powder [13][14][15] . Tacking into account these preliminary considerations, rates of pressure were limited at 5 MPa/min and the maximum pressure was lowered from 200 MPa to 150 MPa.…”

“…Generally, the matrix consolidation has been described in TMC studies [1][2][3][4][5] by using unified mechanical models, despite different mechanisms concerned; above all at the beginning of the densification cycle [11][12][13][14] . For TMC produced by Continuous Binder-Powder Coating, special attention must be made, particularly when heat and pressure are applied in vacuum hot pressing (VHP) for porosity elimination.…”

“…In particular, this article reports the effects of the pressure and temperature during matrix consolidation of 1D-Ti/SiC/C produced by Continuous Binder-Power Coating (CBPC). As previously reported 13 , CBPC process is an alternative fabrication route, in which the fibers are coated by impregnation of a mixing binder/powder producing a concentric binder-powder layer. After coating, the fibers are laid-up unidirectional (1-D) and hot pressed in carbide mould for matrix.…”