Structure of InSb-MnSb Eutectic Alloy by Unidirectional Solidification

Abstract

An eutectic alloy of InSb-MnSb has been unidirectionally solidified at various rates of solidification in order to investigate the structure change due to the solidification condition.
The results obtained are as follows:
(1) The spacing λ between the MnSb rods was expressed to be linear to R^−1⁄2, where R is the rate of solidification, and λ²R was 1.50×10⁻¹⁰ em³/sec.
(2) The alloy specimens consisted of polycrystalline columnar grains which elongated to the solidification direction. The crystallographic orientation relationship between the InSb and MnSb phases was determined by X-ray diffraction. A preferred relationship observed can be stated approximately:
Growth direction: ⟨110⟩InSb\varparallel⟨0001⟩MnSb
Coherent interface: {110}InSb\varparallel{10\bar10} or {11\bar20}MnSb
(3) The phase interface energy between the InSb and MnSb phases was determined from a dislocation model considering the mismatch at the interface and equal to 1.18×10³ erg/cm². Assuming that the crystal growth followed Jackson’s model, and also using this phase boundary energy, the diffusion coefficient was evaluated as D=1.5×10⁻⁵ cm²/sec.