The 14th Global Conference on Materials Science and Engineering
(CMSE 2025)

Abstract: New strategies in the development of metallic composites for advanced structural applications involve the synthesis of bulk materials. Multilayered systems with metallurgical bonding, consisting of two alternating layers of different metals, represent a notable example of such materials. In many cases, the high density of interfaces between layers has a beneficial impact on the overall properties of the composite materials. This effect creates both opportunities and challenges for technological applications, particularly concerning the mechanical response of the material and its ability to shield electromagnetic fields. Since interfaces govern the properties of nano-/micro- composite plates, the evolution of microstructure during the deformation of individual layers and the role of interfaces in composite strengthening remain topics of significant interest.

The aim of this research program was to develop and conduct a detailed structural analysis of multilayered composite materials based on combinations of metals that: (i) form and (ii) do not form intermetallic phases in the solid state. In both systems, local melting and rapid solidification near the interfaces resulted in regions composed of phases with highly varied chemical compositions and structures. The multilayer plates were produced via single-shot explosive welding (EXW). The evolution of the microstructure and phase transformations at all stages of deformation and heat treatment were analysed using advanced scanning (SEM) and transmission (TEM) electron microscopy techniques. These morphological analyses were correlated with phase transformation studies using synchrotron X-ray radiation and mechanical property evaluations via shear strength and micro-/nano- hardness measurements.

In the first group of metal compositions (forming intermetallic phases), this study investigates transformations occurring at the bonding zones of AZ31/AA1050 and Ti (Grade 1)/AA1050 multilayer plates. In the AZ31/AA1050 system, apart from the two equilibrium phases, γ-Mg₁₇Al₁₂ and β-Mg₂Al₃, a significant fraction of the solidified melt regions consisted of non-equilibrium phases exhibiting amorphous or ultrafine-grained structures. During subsequent annealing, a pronounced growth of γ-Mg₁₇Al₁₂ and β-Mg₂Al₃ phases was observed near all interfaces from the early stages of heat treatment, while the phases within the pre-existing reaction regions systematically transformed into the β-Mg₂Al₃ phase. For annealing durations exceeding 10³ hours, an intermediate ε-Mg₂₃Al₃₀ phase layer emerged between the β and γ phase layers. These transformations ultimately converted the initial AZ31/AA1050 multilayer system into a γ-Mg₁₇Al₁₂/ε-Mg₂₃Al₃₀/β-Mg₂Al₃ structure. In the Ti (Grade 1)/AA1050 system, the solidified melt regions were dominated by non-equilibrium phases, with only a minor presence of the crystalline Al₃Ti phase. Heat treatment led to the nucleation of a continuous Al₃Ti phase layer between the Al and Ti sheets, accompanied by the transformation of non-equilibrium phases into structurally heterogeneous Al₃Ti. Conditions determining the transformation of the Ti(Gr.1)/AA1050 multilayer system into a Ti(Gr.1)/Al₃Ti multilayer system were proposed.

In the second group of metal compositions (not forming intermetallic phases), the layers adjacent to the interfaces exhibited complex and hierarchical microstructures. After EXW, the reaction zones consistently comprised a mixture of nanoparticles and fine dendrites of pure Cu and the reactive metals (Ta, Nb, or Fe). Notably, no brittle intermetallic phases were observed near any of the interfaces in these composites. However, the microhardness of the solidified melt regions was 2–3 times higher than that of the annealed base materials, with values of 469 HV, 455 HV, and 480 HV for the Ta/Cu, Nb/Cu, and Cu/Fe-armco combinations, respectively. The large interface area per unit volume was found to enhance both the mechanical properties and electromagnetic shielding effectiveness of the material, offering unique opportunities and challenges for technological applications.

Biography: Professor Henryk Paul received his Doctor of Engineering degree from the Institute of Metallurgy and Materials Science (IMMS) at the Polish Academy of Sciences in Kraków, Poland, in 1989. After serving as an assistant professor, he was promoted to associate professor in 2003 and to full professor in 2010, all at IMMS PAS. He has completed numerous fellowships and internships at French institutions, including an extended stays at the École des Mines de Saint-Étienne and several study visits to LLB Saclay and Université Paris-Sud. He has authored over 290 original papers, 22 book chapters, and 22 review papers on various aspects of phase transformations. His research interests include explosive welding technology, the formation of plastic flow instabilities during the semi-static and high strain rate deformation of metallic materials, recovery and recrystallization phenomena associated with the phase transformations. He has been a plenary, keynote, or invited speaker at 42 international conferences. His publications have been cited over 2,400 times, and he has an h-index of 31.