In-situ fabrication of Bi/BiMn-BiMn-Mn graded materials by high magnetic field gradients

Abstract

In order to develop a new method for in situ fabricating multilayer functionally graded materials (FGMs), high magnetic field gradients are proposed to control the solidification behaviors of peritectic alloys. Solidification experiments of Bi-11.8wt%Mn alloys under various magnetic field gradient conditions have been conducted and the macro- and microstructures of the magnetic field-treated specimens were examined. The primary Mn and βBiMn crystals can successively precipitate during the solidification process. Bi/BiMn-BiMn-Mn FGMs with various gradients have been successfully fabricated during solidification process. The results indicate that the gradient distribution of precipitates could be adjusted by controlling the solidification strategy and the magnetic parameters such as the product of the magnetic flux density and its gradient BdB/dz. © 2010 ISIJ.