Study On The Technology Of High Purity Aluminum Structure Refining

As one kind of key sputtering target material for producing semiconductor chip and TFT-LCD, the high purity aluminum is more and more important in high and new technologies. The quality of the semiconductor chip and TFT-LCD are determined by the high purity aluminum target. The purity and the grains size are the main qualification of the high purity aluminum target. The purpose of this paper is to investigate the effect of Equal Channel Angular Drawing (ECAD) and multiplex forging and rolling on the micromicrostrucutres of high purity aluminum, which will provide a technical support for the high purity aluminum target production.The experiment includes four parts:(1) Self-made ECAD set was used to process high purity aluminum in different routes. The deformed process, drawing pass and the die were changed during ECAD process. The macrostrucutres of the samples after processing were discussed.(2) The effect of multiple forging conditions of high purity aluminum were studied. The deforming microstrucutres of high purity aluminum after forging were got by changing forging passes, cooling and annealing conditions. The macrostrucutres and HV of the samples were analyzed.(3) The effect of rolling conditions of high purity aluminum after forging were studied. The deforming microstrucutres of high purity aluminum after rolling were got by changing rolling temperatures and annealing conditions. The macrostrucutres and HV of the samples were also analyzed.(4) Based on the foregoing work, exploration on refinement of high purity aluminum sheet was proceeded.Experimental results show that:(1) ECAD process had limited capacity to refine the microstrucutre of high purity aluminum, and destabilization occurred frequently.(2) During the multiple forging, the sample had homogeneous and refining microstrucutres when it cooled in water between the forging passes,whose microstrucutres are finer than that without water cooling.(3) As increase in forging passes, the microstrucutres of the difficult deformation zones were effectively refined, the area of the refining zone enlarged, and the grain size decrease at first, then increased.(4) Fine and uniform deforming microstrucutres were achieved in the rolling,and the best process was water cooling between the rolling passes. Annealing after rolling showed that the microstrucutres of samples which was not annealed before rolling were finer than the samples which was annealed before rolling, and the best annealing temperature is200℃.(5) By the multiple forging and rolling process the fine and uniform microstrucutres of large size high purity aluminum plates were produced. The average grain size was about210μm, and it can meet the requirement of the high purity aluminum target.