The Surface Quality Research Of Copper,Aluminum In The Process Of Diffusion Welding

The research Equation of State at high pressure has a very important significance in the field of astrophysics, geophysics, strong loading effects of the materials, laser inertial confinement fusion and so on. In the laser equation of state experimental research, the typical method for determining EOS points is based on the impedance-matching technique. This paper prepares aluminum-copper impedance matching target, with aluminum as standard material, copper as measured material. To decrease the uncertainty of EOS data, the preparation of impedance matching target is put forward to high demands, such as, the initial density of target is required less than95%of the theory of material density; the surface roughness must meet the requirements of very strict, usually less than50nm; the thickness of middle layer is as thin as possible. Comparing various connection methods synthetically, the vacuum diffusion bonding is the best method for preparation of aluminum-copper impedance matching target.This paper select mirror anaerobic copper and pure aluminum as the object of study, first of all, studying the main diffusion process parameters (such as heating temperature and holding time) on the effect of copper, aluminum metal surface quality during the process of diffusion welding. Observing the copper and aluminum metal surface roughness and surface morphology after annealing with the white light interferometer and metallographic microscope. Experiments results show that:when the holding time is1h, with the increasing of heating temperature, copper occurs reply, recrystallization and grain grew up, and surface roughness increases, the heating temperature reaches800℃, grain coarsening, and part of the big grain internal occur with twin and slip band, making the surface roughness sharply increase; When the heating temperatures are controlled in450℃, with the prolongation of holding time, the surface roughness increases, when the holding time is3h, the increase amount of surface roughness starts with reducing, continuing to extend the time of holding time, the increase amount of surface roughness is on the decline, until the surface roughness of copper reaches stable.Aluminum metal easily happens Oxidation reaction, generating a dense layer of oxide film, resulting that the heating temperature and holding time on the influence of aluminum metal surface roughness is small.This paper connects aluminum, copper dissimilar metal film using vacuum diffusion welding technology. Experiments results show that the best technological parameters are the heating temperature of450℃,3Mpa pressure and holding time of1h. after this process conditions, the joint is connection density without diffusion holes.