Vacuum active brazing process for C/C or C/SiC composite material and metal

The invention discloses a vacuum active brazing process for a C/SiC or C/C composite material and metal, which belongs to the technical field of connection of heterostructure materials. The process comprises the following steps of: respectively pretreating a composite material, brazed material and an active brazing material and then placing the active brazing material between the brazed composite material and the metal; vertically applying seal pressure; and then placing a workpiece to be brazed into a vacuum brazing furnace to carry out vacuum brazing. When a difference of the composite material and a metal thermal expansion coefficient is larger, the seal stress is relieved by clamping a metal transition layer between double layers of brazing materials. The invention has the characteristics that by carrying out high-temperature vacuum heat treatment on the composite material, the condition that a volatile matter of the composite material influences the seal quality of the brazing material during vacuum brazing is prevented; the active brazing material and the composite material directly generate physical and chemical reaction, and the gas tightness is good; the seal stress is released by the plastic deformation of transition metal, and the connecting strength is high.