Fabrication And Properties Of Nanotube Reinforced Aluminum Matrix Composite Foam

With the specialty of energy absorption, thermal insulation and noise absorption, aluminum foams has been a research hotspot in engineering domain. However the foaming process has the problem of uncontrollability and bad stability. Relevant studies have shown that the addition of strengthening phase is beneficial for solving the problem of difficulty to control the foaming process and improving the actuality. Carbon nanotubes(CNTs) has a good physical performance and has been regarded as an ideal strengthening phase of metal matrix composite(MMCs). Currently, the conglobatus and bad associativity with matrix of the CNTs become the bottleneck for further study. To make CNTs uniformly distributed in the aluminum surface, a method called chemical vapor deposition(CVD) is introduced to fabricate CNT/Al composites foams. A space-holder method is used for manufacturing open cell aluminum matrix composite foams. The specimen preparing process consists of the CVD, ball milling, mixing, compacting and sintering stages. The porosity, microstructure and compressive property of the foams are characterized.A new process which is based on uniform mixing of CNTs and aluminum powder using CVD method and pore forming materials to prepare foamed matrix composite is proposed. Specifically, the preparation technology of foamed aluminum has been optimized, and the influence on performance by form and dimensions of the pore, and porosity has been analyzed. The CNTs/Al powder with controllable form and dimensions has been made by ball-milling, the pore forming materials have been added to form CNTs reinforced foamed aluminum matrix composite. The influence on compressibility by ball-milling parameters(duration and rotating speed) has been searched. The performance of composite has been compared with that of aluminum foams.The research shows that suppression and sintering of difform urea pill as pore forming materials can be applied in preparation of foamed aluminum matrix composite with controllable porosity, dimensions and form of pore. The optimal forming process has a rotating speed of 400r/min with duration of 2h, pressure of 600 MPa and pressure-maintained duration of 90 s. The sintering process has an argon shield in 650℃ with duration of 3h. The CNTs reinforced foamed aluminum matrix composite of 60% porosity has a maximum compressive strength of 7.12 MPa.