Anisotropic solid–liquid interfacial energy measurement by grain boundary groove method

• Grain boundary groove method was improved for measuring anisotropic interfacial energy.
• 2D grain boundary grooves under a constant temperature gradient were observed.
• Solid–liquid interfacial energy and the anisotropy of pivalic acid were measured.

Solid–liquid interfacial energy and its anisotropy play an important role in microstructure formation during solidification, which is responsible for the final performance of materials. Grain boundary groove (GBG) method has been developed as a common measurement method for the absolute solid–liquid interfacial energy over the past several decades, but it still can’t resolve the anisotropy. In this paper, an improved GBG method for measuring not only the absolute interfacial energy but also the anisotropy was presented and examined in a typical metal analog—pivalic acid (PVA). The equilibrated GBG’s in a quasi-2D sample cell under a constant temperature gradient with different orientation angles were observed in PVA. The GBG shapes, the temperature gradient and the crystal orientation were measured and combined to determine the absolute interfacial energy and the anisotropy of PVA. For comparison, the anisotropy of PVA was also measured independently by equilibrium shape method. The results given by the improved GBG method and equilibrium shape method were consistent. It suggests that the improved GBG method can be used to measure the anisotropic solid–liquid interfacial energy accurately.