Table of Contents

Abstract: As I assume the role of Editor-in-Chief of this new journal, I look forward to serving in contributing to the advance of science and engineering in the field of metallic materials. This formidable task is made possible thanks to the excellent support of the Publisher and of the Editorial Staff of MDPI, as well as to a highly qualified Editorial Board. Hence, it is with pleasure that I accept this challenge, and I look forward to work with all of you in expanding the field of metals through journal contributions of current importance and of great interest to the scientific community. [...]

Abstract: Nanocrystalline Al–Mg dendrites were fabricated through galvanostatic electrodeposition. Initially feather-like morphology was formed exhibiting morphological evolution to smooth globules at its tips. With eventual deposition, rough globules formed over the smooth ones. The feather-like and smooth globules possessed supersaturated face centered cubic (fcc)–Al(Mg) phase with ~7 and ~20 at.% Mg respectively. The rough globules contained hexagonal close packed (hcp)–Mg(Al) phase with ~80 at.% Mg. Microstructural examinations revealed that the feather-like and rough globules possessed grain sizes of ~42 ± 15 and ~36 ± 12 nm respectively. The region, which exhibited morphological evolution from feather-like to smooth globules, possessed ~16 ± 7 nm grain size. The observed microstructural and compositional features were attributed to the local current density values. The formation of the Al–Mg dendrites is discussed in this paper.

Abstract: Control of the material microstructure in terms of the grain size is a key component in tailoring material properties of metals and alloys and in creating functionally graded materials. To exert this control, reliable and efficient modeling and simulation of the recrystallization process whereby the grain size evolves is vital. The present contribution is a review paper, summarizing the current status of various approaches to modeling grain refinement due to recrystallization. The underlying mechanisms of recrystallization are briefly recollected and different simulation methods are discussed. Analytical and empirical models, continuum mechanical models and discrete methods as well as phase field, vertex and level set models of recrystallization will be considered. Such numerical methods have been reviewed previously, but with the present focus on recrystallization modeling and with a rapidly increasing amount of related publications, an updated review is called for. Advantages and disadvantages of the different methods are discussed in terms of applicability, underlying assumptions, physical relevance, implementation issues and computational efficiency.

Abstract: Open cell Al foams have been made by infiltrating molten Al into preforms made from porous salt spheres. Infiltration has been effected using simple pressure-assisted vacuum investment casting where the maximum infiltration pressure difference was less than 36 psi. The preform and resulting foam density decreased with increasing compaction pressure and the foam density increased with increasing infiltration pressure. For low pressure infiltration, and high density preforms, salt dissolution was rapid due to the porous nature of the salt spheres. Infiltration of molten Al occurred into the beads and, for high density preforms and higher infiltration pressures, the volume of metal in the beads exceeded that in the cell walls, drastically decreasing the NaCl dissolution rate. A simple approach is shown whereby the data from mercury porosimetry can be used to predict the resulting foam density, thereby aiding the design of preform and beads structures.

Abstract: The formation of alloys by particle reinforcement during accumulative roll bonding (ARB), and subsequent annealing, is introduced on the basis of the binary alloy system Al-Cu, where strength and electrical conductivity are examined in different microstructural states. An ultimate tensile strength (UTS) of 430 MPa for Al with 1.4 vol.% Cu was reached after three ARB cycles, which almost equals UTS of the commercially available Al-Cu alloy AA2017A with a similar copper content. Regarding electrical conductivity, the UFG structure had no significant influence. Alloying of aluminum with copper leads to a linear decrease in conductivity of 0.78 µΩ∙cm/at.% following the Nordheim rule. On the copper-rich side, alloying with aluminum leads to a slight strengthening, but drastically reduces conductivity. A linear decrease of electrical conductivity of 1.19 µΩ∙cm/at.% was obtained.

Abstract: An alternative deformation technique was applied to a composite made of titanium and an aluminium alloy in order to achieve severe plastic deformation. This involves accumulative swaging and bundling. Furthermore, it allows uniform deformation of a composite material while producing a wire which can be further used easily. Detailed analysis concerning the control of the deformation process, mesostructural and microstructural features and tensile testing was carried out on the as produced wires. A strong grain refinement to a grain size of 250–500 nm accompanied by a decrease in 〈111〉 fibre texture component and a change from low angle to high angle grain boundary characteristics is observed in the Al alloy. A strong increase in the mechanical properties in terms of ultimate tensile strength ranging from 600 to 930 MPa being equivalent to a specific strength of up to 223 MPa/g/cm3 was achieved.

Abstract: The structures realized using sandwich technologies combine low weight with high energy absorbing capacity, so they are suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry) where the “lightweight design” philosophy and the safety of vehicles are very important aspects. While sandwich structures with polymeric foams have been applied for many years, currently there is a considerable and growing interest in the use of sandwiches with aluminum foam core. The aim of this paper was the analysis of low-velocity impact response of AFS (aluminum foam sandwiches) panels and the investigation of their collapse modes. Low velocity impact tests were carried out by a drop test machine and a theoretical approach, based on the energy balance model, has been applied to investigate their impact behavior. The failure mode and the internal damage of the impacted AFS have also been investigated by a Computed Tomography (CT) system.