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This research investigates physical, mechanical, and sliding wear assessment of chromium (0–2 wt% @ step of 0.5 %)-reinforced AA7075 alloy composites (i.e., five composites, namely ACR-0, ACR-0.5, ACR-1, ACR-1.5, and ACR-2). The composition design was fabricated using the stir-casting route. The sample preparation was as per the test standards. Taguchi's approach has been used to design experimental trials and parameter optimization. This follows ANOVA helping in knowing the order of significant factors affecting sliding wear response. The wear sample morphology was studied to understand wear mechanisms. Microstructure studies and X-ray diffraction studies have been reported. It is observed that chromium reinforcement tends to enhance the strength, hardness, and wear performance of the alloy. The voids presence has been successfully arrested. The performance data were analyzed using a hybrid ENTROPY-VIKOR decision-making method. It is observed that the outcome of the decision-making method is in line with the subjective analysis. Thus, ACR-2 alloy composites were observed to optimize the overall performance and hence recommended for structural and tribological applications like gears, slideways, etc. [ABSTRACT FROM AUTHOR]

In this investigation, aluminum alloy (AA2024) composite reinforced with ceramic particulates, namely alumina (Al2O3) and aluminum nitride (AlN), were designed and fabricated through a semi-automatic stir casting route. The ceramics are added complementary (0–4 wt% @ step of 1%), resulting in five composite specimens, namely ON04, ON13, ON22, ON31, and ON40. The composite specimens are then analyzed for their densities, mechanical, and tribological behavior (steady-state sliding wear analysis), adopting ASTM standards. The Taguchi design of experiment technique was adopted for planning test preliminaries and input sliding wear operating parameters (like sliding velocity, sliding distance, normal load, composition, and environment temperature) optimization using ANOVA. Worn surface morphology studies were reported using a scanning electron microscope (SEM) along with energy-dispersive X-ray spectroscopy (EDS) to understand prevalent wear mechanisms in real time. Additionally, a decision-making technique such as the preference selection index (PSI) system was used to analyze the alloy composites ranking. The theoretical densities vary 2.784–2.798 g/cc, while actual densities vary 2.539–2.546 g/cc, and voids fraction vary within the 0.5–9.3 % range. The hardness varies 71.6–85.4 HRB, impact strength varies 54–170 J, and tensile strength varies 190–265 MPa. The ranking orders of the significance of input operating factors are environment temperature > normal load > sliding velocity > reinforcement content > sliding distance. It has been found that the alloy composite sample ON22 with an equal presence of both ceramics exhibits overall optimum mechanical properties as well as superior steady-state behavior, which was consistent with the results of the PSI ranking method. [ABSTRACT FROM AUTHOR]

This present work investigates the physical, mechanical and sliding wear performance of graphite (0–6 wt%)-reinforced ZA-27 alloy composites following ASTM standards. Sliding wear experiments design follows the Taguchi methodology, and the same is adopted for parametric optimization. This follows surface micrograph studies using SEM to understand the associated wear mechanisms responsible for surface damage. Further, the compositions are ranked as per their performance criteria implications using Preference Selection Index (PSI) decision-making technique. It was observed that there are improvements in physical and mechanical properties like void content (2.50–1.33), hardness (107–171 HV), compressive strength (406–496 MPa) flexural strength (300–490 MPa), tensile strength (290–428 MPa) and impact strength (22.76–64 J), as well as sliding wear performance of alloy composites with reinforcement. The AGr-6 alloy composite having 6 wt% graphite particulates were observed to optimize the overall physical, mechanical, and sliding wear performance. The analysis of performance data using the PSI decision-making tool reveals AGr -6 >AGr -4 > AGr -2 > AGr -0 order of material composition that optimizes the required performance. As both decisions are attuned, decision-making tools like PSI could be used in such material selection problems. [ABSTRACT FROM AUTHOR]

In this work, AA7075 ˗ SiC (0–8 wt.% @ step of 2%) / marble dust (8–0 wt.% @ step of 2%) / graphite (3 wt.%) hybrid alloy composites have been designed and fabricated via high vacuum casting method as per standard procedure, leading to five samples namely SM-08, SM-26, SM-44, SM-62, SM-80 respectively. Thereafter, possible synergistic impact of the complementary combination of SiC/marble dust reinforcing particulates on physical, mechanical, and sliding wear performance of hybrid alloy composites were investigated followed by surface morphology studies. Taguchi approach has been used for sliding wear parametric optimization and hybrid ENTROPY-VIKOR decision-making technique is used for ranking of material based on performance measures. It is observed that with the reinforcing phase the properties like wear performance, coefficient of friction, density, voids content, compressive strength, and impact strength of composites increases considerably while flexural strength diminishes. Thus, SM-62 alloy composite (having 6 wt.% SiC, and 2 wt.% marble dust) shows better improved overall performance relative to others. [ABSTRACT FROM AUTHOR]

In this work, hybrid AA2024—Graphite (0-6 wt.% @ 2%)/SiC (2 wt.%)/Si3N4 (2 wt.%) alloy composites were fabricated via semi-automatic stir casting method. The specimens of alloy composites compositions were analyzed to examine the effect of graphite phase reinforcement on the (1) physical and mechanical performance, (2) dry sliding wear/friction performance following ASTM G99 on Pin-on-Disc tribometer. A significant improvement in the physical, mechanical, and wear/friction performance was observed with graphite reinforcing phase. The surface morphology studies revealed the presence of tribo-layer or lubricating layer indicating the presence of solid lubricant graphite. The thickness of tribo-layer enhances with graphite content and accounts for wear/friction performance of hybrid alloy composites. [ABSTRACT FROM AUTHOR]

Abstract: Hollow nanospheres of Sn–Sb–Cu alloy composites have been successfully synthesized via co-reduction of metal chlorides in aqueous alkaline solution without using any surfactants or solid templates. A bubble assisted growth mechanism is proposed to account for the formation of the hollow nanostructures. The concentration of the reactants kinetically controls the nucleation rate of the alloy nuclei, making for the formation of the hollow nanospheres. Compared with the alloy nanoparticles, the hollow spheres exhibit relatively high electrochemical capacity and good cyclic retention when used as anode materials for lithium-ion batteries. The bubble assisted synthesis method can be readily explored for fabricating hollow nanostructure of other alloy system for functional material applications. [Copyright &y& Elsevier]