Intermetallic Phases Identification and Diffusion Simulation in Twin-Roll Cast Al-Fe Clad Sheet

Area of Science:

• Materials Science
• Metallurgy
• Surface Engineering

Background:

• Aluminium steel clad materials offer significant industrial potential.
• Their performance is critically dependent on the intermetallic layer formed at the Al-Fe interface during heat treatment.
• Understanding this interface layer is key to optimizing material properties.

Purpose of the Study:

• To characterize the intermetallic phases at the Al-Fe interface in aluminium steel clad materials.
• To determine the interdiffusion coefficient within these phases.
• To simulate the diffusion process and predict the growth direction of intermetallic layers.

Main Methods:

• Transmission electron microscopy (TEM) for phase identification using selective area electron diffraction (SAED) and energy dispersive spectroscopy (EDS).
• Boltzmann-Matano method to calculate the concentration-dependent interdiffusion coefficient.
• Finite element method (FEM) to simulate the diffusion process.

Main Results:

• Three distinct intermetallic phases were identified: orthorhombic Al₅Fe₂, monoclinic Al₁₃Fe₄, and cubic Al₁₉Fe₄MnSi₂.
• The interdiffusion coefficient exhibited a concentration dependency, peaking at the composition of the intermetallic phases.
• Simulations indicated that the intermetallic phase growth predominantly occurs in the direction of aluminum.

Conclusions:

• The study successfully identified key intermetallic phases and quantified diffusion behavior at the Al-Fe interface.
• The findings provide crucial insights into the growth mechanism of intermetallic layers in aluminium steel clad materials.
• This research aids in the development and application of advanced aluminium steel composites by predicting interfacial layer evolution.