The Growth Behavior for Intermetallic Compounds at the Interface of Aluminum-Steel Weld Joint

Abstract

In this work, the microstructure and growth behavior of Al-Fe intermetallic compounds (IMCs), which formed at interface of weld steel-aluminum joint, are successfully analyzed via the combination of experiment and physical model. A layer IMCs consists of Fe2Al5 and Fe4Al13, in which the Fe2Al5 is the main compound in the layer. The IMCs layer thickness increases with the increase of the heat input and the maximum thickness of IMCs layer is 22 ± 2 μm. The high vacancy concentration of Fe2Al5 IMCs provides the diffusion path for Al atoms to migrate through the IMCs layer for growing towards to steel substrate. By using the calculated temperature profiles as inputs, the combined 2D cellular automata (CA)-Monte Carlo (MC) model is applied to simulate the grain distribution and interfacial morphology evolution at the Al-steel interface. This 2D model simulates the IMCs nucleation, growth, and solute redistribution. The numerical results are in good agreement with the experimental results, suggesting that the growth process can be divided four stages, and the thickness of the Fe2Al5 layer increases nonlinearly with the increase of the growth time. The whole nucleation and growth process experienced 1.7~2 s, and the fastest growth rate is 8 μm/s. The addition of Si element will influence diffusion path of Al atom to form different interface morphology. The effects of peak temperature, cooling time, and the thermal gradient on the IMCs thickness are discussed. It shows that the peak temperature has the major influence on the IMCs thickness.

Microstructure and Mechanical Properties of Resistance Element Welded Joints for DP780 Steel and 6061 Aluminum Alloy

“…The growth of two IMC layers was controlled by the interdiffusion of Fe and Al elements. [42][43][44] To identify phase compositions of the steel/Al alloy interfacial IMC layer, micro-XRD was performed in a 100 μm diameter area at the interface of Al/Q235 steel and Al/DP780 steel, with analysis positions marked as H and I in Figure 4a, and the result of the micro-XRD profile is shown in Figure 10. The micro-XRD profile presents the Fe 2 Al 5 phase and Fe 4 A1 13 phase.…”

Microstructural Inhomogeneity in the Fusion Zone of Laser Welds

“…Therefore, understanding the solidification characteristics of the molten pool and the distribution patterns of grains during the welding process was of paramount importance. Extensive investigations have Materials 2023, 16, 7053 2 of 13 been conducted by employing various techniques, including arc welding [13][14][15], laser welding [16][17][18], and friction stir welding [19][20][21]. Generally, the evolution of the weld solidification mode can be comprehended through the classical theory of constitutional undercooling in the field of solidification [22].…”

Infiltration of aluminum in 3D‐printed metallic inserts

“…The chemical composition, the morphology (whether it is smooth or rough), and the thickness of the intermetallic layer effects the bonding strength [11,12]. Metallic inserts can be fabricated through AM processes since it facilitates the production of complex and interconnected structures such as lattices used for load-transferring applications.…”

“…Regarding the formation of an intimate interface, in the case of dissimilar materials, such as Al and Fe, the formation of intermetallic phases can occur at the interface (e.g., η‐Al 5 Fe). The chemical composition, the morphology (whether it is smooth or rough), and the thickness of the intermetallic layer effects the bonding strength [11, 12].…”