Evaluation of Microstructure of a 6092 Al-17.5 Volume Percent SiC ParticleReinforced Composite Using Electron Backscatter Pattern (EBSP) Analysis Methods

摘要

Microtexture and grain boundary misorientation data were obtained for a 6092 Al-17.5 volume percent SiC particle reinforced material as a function of processing history. Computer aided electron backscatter pattern (EBSP) analysis methods in a scanning electron microscope were used to obtain grain-specific orientation measurements by traversing along a pattern of lines on the surface of a metallographic sample. As part of this project, it was necessary to develop ion milling methods to obtain a sufficiently strain free condition of the aluminum matrix to allow diffraction patterns to be obtained. These methods were applied to samples extruded at various strain rates and processing temperatures; the data revealed that recrystallization had occurred at all processing conditions. Analysis of crystal orientations and grain-to-grain misorientation data revealed random distributions consistent with predictions of the particle-stimulated nucleation theory of recrystallization. Additionally, spacing measurements were taken between orientation measurements, The result of this analysis indicated a very fine matrix micro structure.