A study of interfacial residual stress field in a K2O · 6TiO2w/Al composite by LACBED and 3-D finite element method

The interfacial residual stress field in a K2O · 6TiO2w/Al composite was studied by large angle convergent-beam electron diffraction (LACBED) technique. The diffraction lines near the interface between the Al matrix and the K2O · 6TiO2 whisker became split and twisted when the interface was within the illuminated area. The splitting and shifting of diffraction lines provided information about spatial variation of the residual strain field in the vicinity of whisker. The displacement field near the interface, which was essential to simulation of the LACBED patterns, was calculated with three-dimensional finite element method (3D-FEM) in which the initial strain was one of the adjustable parameters. The initial strain was then determined by fitting the dynamically simulated LACBED patterns to the experimental patterns. The residual stress field in bulk specimen of K2O · 6TiO2w/Al composite was calculated with the obtained initial strain, and compared with that in thin foil specimen. The factors influencing the accuracy in determining the strain/stress field with this method were discussed.