Rough domain surfaces

Figure 1.19 Micrographs of microemulsion droplets of the o/w-type in the system II2O- n-octane-CnEs prepared near the emulsification failure boundary at ya = 0.022, wb = 0.040 and T = 26.1 °C. (a) Freeze-fracture direct imaging (FFDI) picture showing dark spherical oil droplets of a mean diameter = 24 9 nm in front of a grey aqueous background. Note that each oil droplet contains a bright domain of elliptic shape which is interpreted as voids, (b) The freeze-fracture electron microscopy (FFEM) picture supports the FFDI result. Each fracture across droplets which contain bubbles shows a rough fractured surface. (From Ref. [26], reprinted with permission of Elsevier.)...

Figure 8 shows the SEM micrographs of fracture surfaces of both HX-205 and F-185 neat resins. The fracture surface of HX-205 Is very smooth. Indicative of typical brittle fracture behavior. On the other hand, F-185 has a very rough fracture surface. Indicating that the resin was highly strained before fracture occurred. There are also some craters which appear to represent the separation of spheroidal rubber domains from the matrix. 

More general dynamic loading conditions can lead to more complex domains of tensile stress and spall. For example, in a Taylor impact experiment (Kipp and Davison, 1981), where a short cylinder of material is caused to undergo symmetric normal impact on the flat surface of a large block of material, a roughly spherical region within the cylinder is carried into dynamic tension and can undergo spall. 

---