Effect of Vibration on Interdendritic Feeding of AL–5%CU–0.4%MN Alloy

Abstract

In this study, the effect of vibration on the interdendritic feeding of Al–5%Cu–0.4%Mn alloy was investigated using vibration casting experiments and physical simulation. The solidification characteristics of the zinc-oxide paste (used as a mold coating to prevent sand burn during casting) resulted in shrinkage and porosity defects. The experiments were designed to show that vibration can improve feeding and reduce defects. The aqueous solution of sodium carboxmethyl cellulose (CMC) with the same rheological characteristic of metal melt was used in the physical simulation. The seepage calculation model of semisolid fluid in porous media under vibration was established, and the finite difference method and dynamic mesh technique were used to solve the model numerically. The casting results show that vibration can improve the feeding capacity and reduce shrinkage defects of Al–5%Cu–0.4%Mn alloy in gravity sand casting. The physical simulation results show that mechanical vibration can change the blocked structure at the seepage entrance, improve the permeability of porous media and reduce the resistance of interdendritic feeding. Mechanical vibration with the smaller frequency combined with the larger exciting force, or the larger vibration frequency combined with the smaller exciting force, can promote the seepage flow. Meanwhile, the numerical simulation of one-dimensional semisolid fluid seepage reveals that vibration can form a wave field in the porous medium, which can reduce the adhesion force between fluid and the capillary wall and destroy the boundary layer of fluid, thus promoting the seepage velocity.