21. This leads to the decrease of grain boundary strengthening effect. 22. However, a crack that propagates along the grain boundaries is termed an intergranular fracture. 23. Grain boundaries are interfaces where crystals of different orientations meet.24. Some of these maps describe grain orientation, grain boundary , diffraction pattern ( image ) quality. 25. At high temperatures, grain boundaries are weaker than grains. 26. Irregularities at the grain boundaries in materials can produce dislocations which propagate into the grain. 27. Grain boundaries also cause deformation in that they are sources and sinks of point defects.28. The original concentration of solute around the grain boundary will be asymmetrical in most cases. 29. Like a grain boundary , a twin boundary has different crystal orientations on its two sides. 30. Since grain boundaries are defects in the crystal structure they tend to decrease the creep.
