fig7

Figure 7. Snapshots of the bi-crystalline grains with the converging grain boundary (θ₁, θ₂) = (-15°, 15°) in the downward buoyancy ((A) g_y = -g₀/5, (B) g_y = -g₀/2 and (C) g_y = -g₀) and the upward buoyancy ((D) g_y = g₀/5, (E) g_y = g₀/2 and (F) g_y = g₀) when the natural convection is introduced at the beginning of the solidification (t′ = 0).