| 摘要 |
A metal-ceramic composite structure featuring a cavity or other hollow structure therein. The cavity is not cut or machined into the final structure, but rather, is formed during the infiltration process. In the Si/SiC composite materials system in particular, a preform is provided that contains the at least one desired cavity, or an assemblage of subunit preforms are joined together to provide or define at least one cavity. A material that is substantially not infiltratable by the molten infiltrant material is contacted to substantially all interior surfaces, e.g., walls, of the cavity. The contacting can consist essentially of a coating on the walls, or may consist of substantially filling up the cavity with the non-infiltratable material, or some variation in between. Preferably, the non-infiltratable material is in a form that can be readily removed following processing, such as a loosely adhered mass of particulate. The preform or subunit assemblage may then be infiltrated with the molten infiltrant material in the normal way. The infiltrant does not infiltrate into the cavity, it being locally stopped by the non-infiltratable material at the walls of the cavity. Following solidification of the infiltrant to form a RBSC body, the non-infiltratable material is removed readily, for example by air or water jets, shaking, vacuuming, etc. In addition, one or more temporary access ports to the cavity may be machined in the composite structure, for example, to provide additional access to the pressure jet or vacuum means, the access ports being re-sealed following removal of the non-infiltratable material. |
