Research On Preparation And Forging Of Thin-wall Part With High Volume Fraction SiC_P/Al-AA6061

The high volume fraction Si C_P/Al composites with high thermal conductivity, low thermal expansion coefficient and density meet electronic packaging performance requirements of aerospace. However, the forging and joining method is the main difficulty of the study. Hence, the interfacial humidity and reactions of Si C_P/Al in practical application is the center part of the research.This thesis studies the influence of different elements on the thermal conductivity and expansion coefficient of Si C_P/Al composite via the finite element method, such as different Si C particle size, volume fraction, particle shape and the oxide layer thickness.Using semi-solid forging method to make Si C_P/Al composite of different content of Mg, Si and Si C; to observe the microstructure, phase and interface by using OM, SEM and TEM; and to test the density, bending strength, thermal conductivity and expansion coefficient.The previous experiments use semi-solid forging and joining technology, to explore the influence of different parameters on the forging and joining effect of Si C_P/Al-Al thin-wall part. And the analysis on interfacial microstructure and shearing strength provides a reference for the elements control and preparation of high volume fraction Si C_P/Al composites.Results of the simulation part: 1. Little effect of the particle size and shape on the thermal conductivity and expansion coefficient of Si C_P/Al composites; 2. Linear decrease of the thermal conductivity and expansion coefficient with the increase of volume fractions of Si C, conform with the rule of mixtures; 3. Rapid decrease of the thermal conductivity and finally slowing down with the increase of Si C oxide thickness.Results of the experiments: 1. The increase the content of Mg in the matrix, can improve the density, bending strength and thermal conductivity of Si C_P/Al composites, which helps reduce the thermal expansion coefficient, but can’t avoid the by-product of Al4C3. 2. The increase the content of Si in the matrix has little effect on the density of Si C_P/Al composites, but reduces the bending strength and thermal conductivity and expansion coefficient and a rightful amount of Si can avoid Al4C3. 3. The improvement of volume fraction of Si C can reduce the density, bending strength and thermal conductivity of Si C_P/Al composite, which helps to reduce the thermal expansion coefficient.By comparing different heating temperature, insulation time and Si C volume fraction, the thin-wall part with 55 vol.% Si C_P/Al-AA6061, at a heating temperature of 665 oC and 9-minute insulation, the forging and joining works best; and the improvement of Si C volume fraction can reduce the interfacial shearing strength.