Fabrication Process And Microstructure Of Laminated Woven Fiber Reinforced Al Matrix Composite Manufactured By Hot Pressing Diffusion Bonding

Carbon fiber reinforced aluminum matrix composites have superior performance of lightweight, high strength and high stiffness, and also have better temperature performance and corrosion resistance, stability. Carbon fiber reinforced aluminum matrix composites are much concerned in aerospace and national defense, and have been developed into one of most strategic of structural materials. The traditional molding processes include liquid state and solid state methods. Laminated woven fiber reinforced aluminum matrix composites were prepared by vacuum hot pressing diffusion method. The study focused on the effects of hot pressing temperature,holding time and pressure and other process parameters on compactness,microstructure, interfacial reaction and mechanical property of composites. In addition, the paper also discussed the change of mold temperature field. The main conclusions are as follows.When furnace temperature is 610℃, 620℃ and 630℃, mold center temperature increase with the furnace thermal insulation time in the range of 0-50 min.When the furnace thermal insulation time is in the range of 80-120 min, mold center temperature is basically stable. When the furnace thermal insulation time reaches 80 min, mold center temperature are 608℃, 617℃, 626℃, differ with furnace temperature of 2℃,3℃, 4℃ respectively. Counting hot holding time as the furnace thermal insulation time reaches 80 min, stable hot pressing temperature can be obtained. As the holding time prolonging, mould center temperature closing to the furnace temperature.Hot pressing temperature is critical process parameter of laminated woven fiber reinforced aluminum matrix composites manufactured by vacuum hot pressing diffusion method. The parameters of hot pressing technique optimized by orthogonal experiments are as follows. The process parameters of hot pressing temperature 626℃,holding time 50 min, pressure 20 MPa are optimal process parameters. The composites compactness reaches 99.05% under these process parameters. Within a certain range,with the increasing of the hot pressing temperature, holding time and pressure, density increasing.The aluminum matrix composite was prepared successful by vacuum hot pressing diffusion method. Bi-directional carbon fibers distribute in the aluminum matrix evenly, the composite is uniform and dense in microstructure. The interface formed by aluminum matrix with carbon fibers combine more closely; No defects such as pores and impurity are formed. The interface formed by aluminum matrix with carbon fiber is rough interface. Rod-shaped Al4C3 is formed in the interface, the approximate content of Al4C3 is 3.6%.The tensile strength increases as increasing of hot pressing temperature, holding time and pressure of laminated woven fiber reinforced aluminum matrix composites.Under the process conditions of hot pressing temperature 626℃, holding time 50 min,pressure 20 MPa, the tensile strength of composites reached 98.52 MPa. And with the increasing of the hot pressing temperature, holding time and pressure, the tensile strength of composite shows a trend of increasing as a whole.Composites fracture shows rugged, lots of carbon fiber are pulled out. And shows low-stress damage, part of the carbon fibers breakage, composites fracture performances typical brittle fracture. EDS analysis through the interface consists mainly of C, O and Al elements. C, Al4C3 and Al2O3 forms exist in the junction of carbon fibers and aluminum.