Numerical analysis of flow and heat transfer in the melt puddle of planar flow casting for Fe-Cu-Nb-Si-B amorphous ribbons

• Fish-scale patterns with a period of 0.22-0.6 mm were simulated using a 3D VOF model. • Analyzed the movement process of air-pockets in the melt puddle within 0.949-0.967 ms. • The ribbon thickness has been reduced by 20.76-50% within the adjustment range. A coupled air-melt two-phase flow three-dimensional (3D) Volume of Fluid (VOF) model was established to simulate the melt puddle formation process during planar flow casting (PFC) of Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 amorphous ribbons, based on the continuity equation, momentum equation, and energy equation. The 3D melt puddle behavior was studied. The causes of the fish-scale patterns were analyzed. A two-dimensional (2D) simplified model was employed to investigate the effects of various parameters on the shape characteristics of the melt puddle and the ribbon thickness, yielding the optimal parameter combination for producing thinner amorphous ribbons. The results indicate that the flow and heat transfer characteristics of the melt puddle exhibit distinct 3D distribution features, with the cooling rate in the middle being significantly lower than that on both sides. Based on the temperature-viscosity curve obtained from experimental tests, fish-scale patterns with a period ranging from 0.22 mm to 0.6 mm were simulated. It was found that periodically entrained air-pockets are rapidly dragged out of the melt puddle with the melt, forming the periodic fish-scale patterns. The distance between two air-pockets is one period of the fish-scale pattern. This makes it possible for PFC to control the fish-scale patterns. With the increase of the U, the decrease of the V, the reduction of the W and the G, the thickness of the ribbon decreases by 20.76%-50% within the selected range. This may explore the minimum thickness for preparing amorphous ribbons.