Enhancing Tribological Performance of Self-Lubricating Composite via Hybrid 3D Printing and In Situ Spraying.

In this work, a self-lubricating composite was manufactured using a novel hybrid 3D printing/in situ spraying process that involved the printing of an acrylonitrile butadiene styrene (ABS) matrix using fused deposition modeling (FDM), along with the in situ spraying of alumina (Al2O3) and hexagonal boron nitride (hBN) reinforcements during 3D printing. The results revealed that the addition of the reinforcement induced an extensive formation of micropores throughout the ABS structure. Under tensile-loading conditions, the mechanical strength and cohesive interlayer bonding of the composites were diminished due to the presence of these micropores. However, under tribological conditions, the presence of the Al2O3 and hBN reinforcement improved the frictional resistance of ABS in extreme loading conditions. This improvement in frictional resistance was attributed to the ability of the Al2O3 reinforcement to support the external tribo-load and the shearing-like ability of hBN reinforcement during sliding. Collectively, this work provides novel insights into the possibility of designing tribologically robust ABS components through the addition of in situ-sprayed ceramic and solid-lubricant reinforcements.

The Role of Lithium-Ion Batteries in the Growing Trend of Electric Vehicles.

Within the automotive field, there has been an increasing amount of global attention toward the usability of combustion-independent electric vehicles (EVs). Once considered an overly ambitious and costly venture, the popularity and practicality of EVs have been gradually increasing due to the usage of Li-ion batteries (LIBs). Although the topic of LIBs has been extensively covered, there has not yet been a review that covers the current advancements of LIBs from economic, industrial, and technical perspectives. Specific overviews on aspects such as international policy changes, the implementation of cloud-based systems with deep learning capabilities, and advanced EV-based LIB electrode materials are discussed. Recommendations to address the current challenges in the EV-based LIB market are discussed. Furthermore, suggestions for short-term, medium-term, and long-term goals that the LIB-EV industry should follow are provided to ensure its success in the near future. Based on this literature review, it can be suggested that EV-based LIBs will continue to be a hot topic in the years to come and that there is still a large amount of room for their overall advancement.

Solid-State Cold Spray Additive Manufacturing of Ni-Based Superalloys: Processing-Microstructure-Property Relationships.

Ni-based superalloys have been extensively employed in the aerospace field because of their excellent thermal and mechanical stabilities at high temperatures. With these advantages, many sought to study the influence of fusion-reliant additive manufacturing (AM) techniques for part fabrication/reparation. However, their fabrication presents many problems related to the melting and solidification defects from the feedstock material. Such defects consist of oxidation, inclusions, hot tearing, cracking, and elemental segregation. Consequentially, these defects created a need to discover an AM technique that can mitigate these disadvantages. The cold spray (CS) process is one additive technique that can mitigate these issues. This is largely due to its cost-effectiveness, low temperature, and fast and clean deposition process. However, its effectiveness for Ni-based superalloy fabrication and its structural performance has yet to be determined. This review aimed to fill this knowledge gap in two different ways. First, the advantages of CS technology for Ni-based superalloys compared with thermal-reliant AM techniques are briefly discussed. Second, the processing-structure-property relationships of these deposits are elucidated from microstructural, mechanical, and tribological (from low to high temperatures) perspectives. Considering the porous and brittle defects of CS coatings, a comprehensive review of the post-processing techniques for CS-fabricated Ni superalloys is also introduced. Based on this knowledge, the key structure-property mechanisms of CS Ni superalloys are elucidated with suggestions on how knowledge gaps in the field can be filled in the near future.

Ultrasonic Nanocrystal Surface Modification: Processes, Characterization, Properties, and Applications.

Ultrasonic nanocrystal surface modification (UNSM) is a unique, mechanical, impact-based surface severe plastic deformation (S2PD) method. This newly developed technique finds diverse applications in the aerospace, automotive, nuclear, biomedical, and chemical industries. The severe plastic deformation (SPD) during UNSM can generate gradient nanostructured surface (GNS) layers with remarkable mechanical properties. This review paper elucidates the current state-of-the-art UNSM technique on a broad range of engineering materials. This review also summarizes the effect of UNSM on different mechanical properties, such as fatigue, wear, and corrosion resistance. Furthermore, the effect of USNM on microstructure development and grain refinement is discussed. Finally, this study explores the applications of the UNSM process.