Measurement of grain boundary triple line energy in copper

Recent studies have demonstrated that grain boundary triple junctions are crystal defects with specific thermodynamic and kinetic properties. In this study we address the energy of triple lines. Previously, a geometrical model was proposed to determine the grain boundary line tension. The current study introduces a thermodynamically correct approach which allows direct and precise measurement of the triple line energy. The experimental technique utilizes the measurement of the surface topography of a crystal in the vicinity of a triple junction by atomic force microscopy. The grain boundary triple line tension γTPl of a random triple line in a copper tricrystal was measured to be 6.3 ± 2.8 × 10−9 J m-1.