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The May 2024 issue of the Journal of Materials Science features a cover paper titled "Role of stacking fault energy in confined layer slip in nanolaminated Cu" by Ji et al. The paper explores the deformation of metallic nanolaminates and acknowledges the contribution of Professor Hussein Zbib. The issue is dedicated to honoring Professor Zbib's memory and was conceived by Guest Editors Tariq Khraishi, Georges Ayoub, Sinisa Mesarovic, and Mutasem Shehadeh. The paper includes references to previous work but does not mention any measurements of the intrinsic stacking fault energy. The corresponding author is Professor Shuozhi Xu from the University of Oklahoma, and the last author is Professor I.J. Beyerlein, who has a background in research and was born in Los Alamos. The paper is freely accessible through the SharedIt link provided. [Extracted from the article]

In the paper, near-net shape fabrication (ball milling, cold pressing, and microwave sintering) of Fe-6.5 wt%Si steel strip was carried out on the basis of the rapid solidification single-roll spinning, and the micromorphology transformation, texture evolution, mechanical and magnetic properties of the obtained samples were studied. This process could not only prepare samples with good mechanical and magnetic properties, but also achieve near-clean shape treatment. The results show that the refinement and homogenization of grain and the evolution of texture (the disappearance of γ-texture and the formation of Goss texture) play a good role in improving the mechanical and magnetic properties. The sample prepared by 1200 °C microwave sintering has excellent magnetic properties of Ms = 232.54 emu/g, Hc = 32.27 Oe, and Mr = 3.13 emu/g, and it also has the highest Vickers hardness of 212.32HV. [ABSTRACT FROM AUTHOR]

Through Silicon Via (TSV), a kind of 3D packaging technique, can improve chip integration based on "More than Moore" scheme. The larger copper area ratio at the TSV barrier layer interface requires strong adjustability of the removal rate selection ratio of copper, tantalum and TEOS–SiO2, and stronger surface defect control and surface profile correction capabilities. In this paper, the effects of guanidine hydrochloride (GH) and 2,2′-[[(Methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol (TT-LYK) system on the tunability of Ta and Cu removal rate in chemical mechanical polishing (CMP) of TSV wafer barrier material were studied. GH can complex TaO 4 3 - , while TT-LYK can form a protective film on the surface of Cu, thereby achieving rate regulation. The results showed that when the concentration of GH increased from 0 to 2 wt%, the removal rate selectivity ratio of Ta and Cu raised from 1.02:1 to 1.26:1. When the concentration of TT-LYK increased from 2.5 to 10 mmol/L, the removal rate selectivity ratio of Ta and Cu increased from 1.33:1 to 1.79:1, which verified that the GH and TT-LYK systems can efficiently regulate the rate and rate selection ratio of Ta and Cu. Surface roughness for both metals decreased from pre-polishing values of 5.03 nm to post-polishing values of 0.37 nm for Ta, from pre-polishing values of 5.33 nm to post-polishing values of 1.26 nm for Cu indicating that GH and TT-LYK systems significantly improved the surface quality. [ABSTRACT FROM AUTHOR]

The regulation of hydrogen content in the continuous casting process is conducive to the reduction of pore defects in the casting billet. In this paper, the influence of negative pressure (NP) and continuous casting speed (CCS) on hydrogen content in copper rod billet prepared by negative pressure continuous casting (NPCC) technique was analyzed, and the mechanism of the coordinated coupling of NP and melt flow on hydrogen removal was revealed. It is clarified that with the CCS of 20 mm min−1 and an increase in the NP value from − 20 to − 80 kPa, the hydrogen content is reduced from 1.0 to 0.3 ppm. The coordinated action of NP and melt flow induced by CCS can minimize the hydrogen content. When the NP value is − 80 kPa and the CCS is 10 mm min−1, the hydrogen content is as low as 0.2 ppm, and the hydrogen removal rate is 85.7%. The larger the NP, the smaller the critical nucleation radius of the hydrogen bubble, and the larger the growth rate of the hydrogen bubble. The coupling of the NP field and flow field can make the melt which is difficult to nucleate and grow of the hydrogen bubble flow to the position which is easy to nucleate and grow. The effect of the vortex fields in the purification chamber on the removal of hydrogen is not affected by the CCS, but the CCS affects the floating of hydrogen at the solidification front, which leads to a small increase in the hydrogen content with the increase of the CCS. Our study provides a theoretical basis for the preparation of high-quality metal billets. [ABSTRACT FROM AUTHOR]

In this paper, high-density (60−x)Fe−Cr−Co−xCu (x: 0–6 wt.%) permanent magnet alloys were fabricated by laser powder bed fusion (LPBF) in-situ alloying technique, and the effects of Cu content on the microstructure, magnetic, and mechanical properties of the alloy were systematically investigated. The addition of 2 wt.% Cu enhanced the coercivity H c and the energy product (B H) max of the alloy in the isotropic state by 19.4 and 27.9%, respectively, compared to the alloy without Cu. The impacts of Cu content on the magnetic properties were investigated by combining experimental results and first-principles calculations. Furthermore, the addition of Cu improved the yield strength of the alloy, and the strengthening mechanism was analyzed in detail. The yield strength of the alloy with 2 wt.% Cu reached 908 MPa, representing a notable 7% increase relative to the Cu-free alloy. [ABSTRACT FROM AUTHOR]

With the continuous downsizing of solder joints, the influence of the grain characteristics of the under bump metallization (UBMs) on the interfacial reaction is exposed. In this paper, the effect of grain characteristics of Cu UBM on the growth of interfacial intermetallic compounds and the formation of Kirkendall voids in Cu/Sn/Cu micro solder joints during isothermal aging at 150 °C was investigated. Electroplated polycrystalline Cu (EP-Cu), (111) single crystal Cu ((111) Cu), and (111) nano-twinned Cu ((111) nt-Cu) were selected as UBMs. After reflow soldering, the Cu6Sn5 grains formed on (111) nt-Cu were near to the orientation (2 1 - 1 - 3) , while those were randomly formed on both EP-Cu and (111) Cu. During isothermal aging, the Cu6Sn5 grains exhibited the highest growth rate on (111) nt-Cu UBM, and the slowest growth rate on (111) Cu UBM, due to the differing number of diffusion routes among the three Cu UBMs with distinct grain characteristics. Furthermore, no Kirkendall voids were detected on the (111) Cu UBM, however, a significant number of Kirkendall voids were identified on the (111) nt-Cu UBM, which can be attributed to the diffusion path and impurities present in the three Cu UBMs. The results will offer theoretical and practical recommendations for the selection of Cu UBMs for micro solder joints in 3D packaging interconnection technology. [ABSTRACT FROM AUTHOR]

Solar-driven interfacial evaporation is a sustainable and green desalination method with great prospects for development in today's severe water shortage problem. In this paper, a novel composite aerogel was prepared by hydrothermal method with sodium alginate (SA) and Cu2+ in the preparation process using reduced graphene oxide as photothermal material and cellulose nanofibers as substrate. The good hydrophilicity of nanocellulose makes the composite aerogel have strong capillary action and continuous water transport. The gel formed by ion exchange between SA and Cu2+ greatly improves dry and wet mechanical strength of the composite aerogel and ensures the stability of the evaporator for multiple recycling. Copper is doped by reduction of copper ion complexes and reduced graphene oxide have a synergistic effect to increase the photothermal response rate of the composite aerogel of 1.446 kg m−2 h−1 with evaporation efficiency of 84.87% under one standard solar irradiation. In addition, the purification of heavy metal ions, dye wastewater as well as acid and alkali solutions also has excellent results. It is expected that this study will provide some new ideas for the fields of seawater desalination and wastewater treatment. [ABSTRACT FROM AUTHOR]

The demolding process of electroforming technology in fabricating microstructured optical-functional thin films produces the problem of excessive bonding between the metal substrate and the metal replica, which triggers the deformation of the microstructure and the reduction of precision, and the deposition of Cr–O–C discrete nuclei at the interface can play a good role in assisting the demolding effect. In this paper, the tensile deformation of polycrystalline Cu/Ni and Cu/Cr–O–C/Ni composites is investigated using molecular dynamics methods. The results show that the Cu/Ni model produces a large number of HCP structures during stretching, with holes at the interface and a large number of Cu atoms transferring to the Ni layer. The addition of the Cr–O–C layer reduces the yield strength of the Cu/Cr–O–C/Ni model by 26.41%, and at the same time, the dislocation proliferation at the interface is reduced, and the fracture is at the centralized interface, and the fracture time is reduced by 90.8%. The higher number of Cr–O–C atoms at the interface decreases the transfer of Cu atoms to the Ni layer. The results provide a possible explanation for the Cr–O–C layer-assisted precision electrodeposition debonding. [ABSTRACT FROM AUTHOR]

Mo/Cu composites exhibit significant potential for applications in electronic packaging and other domains. However, the diffusion process and mechanism of Mo/Cu composites are difficult to experiment with. Therefore, in this paper, a new potential function is first constructed and verified for the Mo/Cu system. The Mo/Cu diffusion process is studied on the atomic scale by molecular dynamics (MD) simulation. The conditions for rapid diffusion of Mo/Cu are determined at 1000 K and Mo (100) interface orientation. The vacancy diffusion mechanism in the Mo/Cu system is elucidated through the analysis of the diffusion results. Finally, the diffusion under an external electric field is simulated, and the critical condition for diffusion is determined by increasing the vacancy concentration. The diffusion temperature can be reduced by about 100 K at E = 0.002 V/Å. This study can provide theoretical support for the electro-assisted preparation of Mo/Cu composites.Graphical abstract: Mo/Cu composites exhibit significant potential for applications in electronic packaging and other domains. However, the diffusion process and mechanism of Mo/Cu composites are difficult to experiment with. Therefore, in this paper, a new potential function is first constructed and verified for the Mo/Cu system. The Mo/Cu diffusion process is studied on the atomic scale by molecular dynamics (MD) simulation. The conditions for rapid diffusion of Mo/Cu are determined at 1000 K and Mo (100) interface orientation. The vacancy diffusion mechanism in the Mo/Cu system is elucidated through the analysis of the diffusion results. Finally, the diffusion under an external electric field is simulated, and the critical condition for diffusion is determined by increasing the vacancy concentration. The diffusion temperature can be reduced by about 100 K at E = 0.002 V/Å. This study can provide theoretical support for the electro-assisted preparation of Mo/Cu composites. [ABSTRACT FROM AUTHOR]

Cuprous oxide (Cu2O) nano- and microstructures possess unique properties that may find a variety of applications. Environmentally benign synthesis of Cu2O with well-controlled morphology is highly desirable. In this study, Cu2O crystals with tunable shapes are synthesized using cellulose nanofibrils (CNFs) as a shape regulator and the sole reducing agent in aqueous environment. By simply increasing Cu2O precursor concentration, the Cu2O crystals evolved from octahedra to cuboctahedra, and finally cubes, accompanied with increasing size from nano- to microscale. The selection of Cu chelating agent (sodium tartrate or potassium sodium tartrate) affected the crystal growth rate. Transition in the relative intensities of the (111) and the (200) crystalline peaks in their XRD patterns was consistent with the morphology change. During the growth of crystals, CNFs were preferably bound to the {111} crystalline facet. The introduction of KBr to the reaction system produced short hexapods. The resultant CNF-Cu2O hybrids were incorporated into waterborne polyurethane (WPU) films. Even with 0.5 wt% CNF-Cu2O, the WPU film showed significant enhancement in modulus, strength and elongation at break. This work proves the possibility of controlled growth of Cu2O particles aided by CNFs and provides a new strategy for improving the performance of eco-friendly WPU films. [ABSTRACT FROM AUTHOR]