Metallurgical, mechanical and tribological behavior of Reinforced magnesium-based composite developed Via Friction stir processing

Reinforced magnesium metal matrix nanocomposites (MMMNCs) have piqued the interest of scientific community in recent years. Friction stir processing (FSP) is a known process to achieve the highest level of secondary phase nanocomposites distribution in the base monolithic matrix. In this study, an attempt has been made to synthesize magnesium base AZ61A/n-TiC nanocomposites using FSP and the influence of tool rotational speed on the metallurgical, mechanical, and tribological behavior of the developed composites has been studied. Microstructural examination shows that as tool rotational speed increases, high plastic deformation occurs and heat is generated along with the concomitant shattering impact of rotation, which consequently develops larger grains in the stir zone. However, this also provides thrusts resulting in uniform distribution of the nanoparticles in the base matrix. Microhardness and ultimate tensile strength of the developed nanocomposite were found to be significantly improved when contrasted with the base metal. Lower wear rate was observed for the composite developed at 800 rpm along with the abrasive type of wear mechanism.

Determining the Self-Limiting Electrospray Deposition Compositional Limits for Mechanically Tunable Polymer Composites

Electrospray deposition (ESD) is a versatile micro/nano coating technology that utilizes the competition between surface charge of a droplet and its surface tension to create monodisperse generations of micro/nano droplets. ESD can deposit uniform thin films by including dilute solutes in these droplets. One mode of ESD, self-limiting electrospray deposition (SLED), has been shown to exist when glassy polymers are sprayed in a volatile solvent below the polymer glass transition temperature (Tg). This leads to charge accumulation on the coating surface that slows the growth of the film thickness. Since solutes can be easily blended in dilute ESD solutions, we investigate the SLED limits of self-limiting and non-self-limiting solute blends. As a motivating application, we focus on mechanical properties of the film. Specifically, we blend self-limiting polystyrene (PS) and SU-8 epoxy resin with different non-self-limiting mechanical modifiers, such as plasticizers and curing agents. To characterize the resulting morphologies and mechanical properties, we employ scanning electron microscopy and nanoindentation of as received and smoothed films. The results illustrate the formation of composited polymers that exhibit self-limiting ability by SLED, depending on the interaction between the two components. Further, mechanical properties could be effectively fine-tuned within these compositional ranges. This signifies the 3D coating capabilities through SLED can be implemented incorporating additional functionalities and properties beyond the base matrix.

APPLICATION OF WC GRAINS BY DEPOSITION BRAZING

The article describes problems of hard depositional brazing of wolfram-carbide grains in various matrixes. Especially iron and nickel base matrix on base material from constructional carbon steel. The experimental part was brazed by oxyacetylene flame (method 912 according to EN ISO 4063). The major goals of the experiment were to describe the technological procedure of hard depositional brazing of this specific part. Consequently, were proved wolfram-carbide deposit on two test coupons. These test coupons were metallographically and qualitatively evaluated. The advantage of wolfram-carbide depositional brazing is a service life of deposit, that could be multiple higher, than standard weld deposit with carbon, chromium and vanadium filler material. The advantage is also costly because this kind of braze is cheaper than hard surfacing filler material. This specific application of the wolfram-carbide layer is one of the hardest coatings that could be by flame brazing technology performed. Usage of this application is for example in the mining, woodcutting industry, where it is necessary to improve abrasion and resistance, service life, and guaranteed durability or hardness for cutting tools.

Electrical and Structural Properties of Li1.3Al0.3Ti1.7(PO4)3-Based Ceramics Prepared with the Addition of Li4SiO4

The currently studied materials considered as potential candidates to be solid electrolytes for Li-ion batteries usually suffer from low total ionic conductivity. One of them, the NASICON-type ceramic of the chemical formula Li1.3Al0.3Ti1.7(PO4)3, seems to be an appropriate material for the modification of its electrical properties due to its high bulk ionic conductivity of the order of 10−3 S∙cm−1. For this purpose, we propose an approach concerning modifying the grain boundary composition towards the higher conducting one. To achieve this goal, Li4SiO4 was selected and added to the LATP base matrix to support Li+ diffusion between the grains. The properties of the Li1.3Al0.3Ti1.7(PO4)3−xLi4SiO4 (0.02 ≤ x ≤ 0.1) system were studied by means of high-temperature X-ray diffractometry (HTXRD); 6Li, 27Al, 29Si, and 31P magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR); thermogravimetry (TG); scanning electron microscopy (SEM); and impedance spectroscopy (IS) techniques. Referring to the experimental results, the Li4SiO4 additive material leads to the improvement of the electrical properties and the value of the total ionic conductivity exceeds 10−4 S∙cm−1 in most studied cases. The factors affecting the enhancement of the total ionic conductivity are discussed. The highest value of σtot = 1.4 × 10−4 S∙cm−1 has been obtained for LATP–0.1LSO material sintered at 1000 °C for 6 h.

Revalorization of Pleurotus djamor Fungus Culture: Fungus-Derived Carbons for Supercapacitor Application

Currently, there is increasing interest and effort directed to developing sustainable processes, including in waste management and energy production and storage, among others. In this research, corn cobs were used as a substrate for the cultivation of Pleurotus djamor, a suitable feedstock for the management of these agricultural residues. Revalorization of this fungus, as an environmentally friendly carbon precursor, was executed by taking advantage of the intrinsic characteristics of the fungus, such as its porosity. Obtaining fungus-derived porous carbons was achieved by hydrothermal activation with KOH and subsequent pyrolysis at 600, 800, and 1000 °C in an argon atmosphere. The morphologies of the fungal biomass and fungus-derived carbons both exhibited, on their surfaces, certain amorphous similarities in their pores, indicating that the porous base matrix of the fungus was maintained despite carbonization. From all fungus-derived carbons, PD1000 exhibited the largest superficial area, with 612 m2g−1 and a pore size between 3 and 4 nm recorded. Electrochemical performance was evaluated in a three-electrode cell, and capacitance was calculated by cyclic voltammetry; a capacitance of 60 F g−1 for PD1000 was recorded. Other results suggested that PD1000 had a fast ion-diffusion transfer rate and high electronic conductivity. Ultimately, Pleurotus djamor biomass is a suitable feedstock for obtaining carbon in a sustainable way, and it features a defined intrinsic structure for potential energy storage applications, such as electrodes in supercapacitors.

Advanced Self-Passivating Alloys for an Application under Extreme Conditions

Self-passivating Metal Alloys with Reduced Thermo-oxidation (SMART) are under development for the primary application as plasma-facing materials for the first wall in a fusion DEMOnstration power plant (DEMO). SMART materials must combine suppressed oxidation in case of an accident and an acceptable plasma performance during the regular operation of the future power plant. Modern SMART materials contain chromium as a passivating element, yttrium as an active element and a tungsten base matrix. An overview of the research and development program on SMART materials is presented and all major areas of the structured R&D are explained. Attaining desired performance under accident and regular plasma conditions are vital elements of an R&D program addressing the viability of the entire concept. An impressive more than 104-fold suppression of oxidation, accompanied with more than 40-fold suppression of sublimation of tungsten oxide, was attained during an experimentally reproduced accident event with a duration of 10 days. The sputtering resistance under DEMO-relevant plasma conditions of SMART materials and pure tungsten was identical for conditions corresponding to nearly 20 days of continuous DEMO operation. Fundamental understanding of physics processes undergone in the SMART material is gained via fundamental studies comprising dedicated modeling and experiments. The important role of yttrium, stabilizing the SMART alloy microstructure and improving self-passivating behavior, is under investigation. Activities toward industrial up-scale have begun, comprising the first mechanical alloying with an industrial partner and the sintering of a bulk SMART alloy sample with dimensions of 100 mm × 100 mm × 7 mm using an industrial facility. These achievements open the way to further expansion of the SMART technology toward its application in fusion and potentially in other renewable energy sources such as concentrated solar power stations.

Effects of MgO Powder addition on mechanical, physical and thermal properties of Al waste bagasse composite

Environmental pollution from various industries is a serious issue in most countries. Bagasse is a waste product from sugar factory industries. Bagasse pollutes the soil and the air. In the present investigation, an attempt has been made to utilize bagasse waste as a primary reinforcement material in the development of an aluminum-based metal matrix composite. Magnesium oxide (MgO) powder was mixed with bagasse ash to enhance the wettability of the bagasse ash and the aluminum matrix. The microstructure results of the bagasse reinforced hybrid composite showed a proper distribution of carbonized bagasse ash and MgO powder in the aluminum base matrix material. Minimum porosity and minimum corrosion loss were measured at 1.43 % and 0.05 mg, respectively for a selected composition Al+2.5 wt.-% carbonized bagasse ash +12.5 wt.-% MgO hybrid metal matrix composite. The composition of the Al+10 wt.-% carbonized bagasse ash metal matrix composite exhibited the maximum specific strength of 39.59 kN × m × kg-1 which is much better than than that of the base matrix material. In addition, as the percentage of reinforcement in the casting increases, the cost and density of the final cast composite reinforced by bagasse, continually decrease. Sample G13 (Al+ 5 wt.-% carbonized bagasse ash + 10 wt.-% MgO powder) shows a small change in dimensions due to thermal expansion.

Digital transformation success under Industry 4.0: a strategic guideline for manufacturing SMEs

PurposeThe digital transformation under Industry 4.0 is complex and resource-intensive, making a strategic digitalization guideline vital to small and medium-sized enterprises' success in the Industry 4.0 transition. The present study aims to provide manufacturing small and medium-sized enterprises (SMEs) with a guideline for digital transformation success under Industry 4.0.Design/methodology/approachThe study first performed a content-centric literature review to identify digital transformation success determinants. The study further implemented interpretive structural modeling to extract the order at which the success determinants should be present to facilitate the SMEs’ digital transformation success optimally. The interpretive model and interpretive logic knowledge base matrix were also used for developing the digital transformation guideline.FindingsEleven success determinants are vital to SMEs’ digital transformation efforts. For example, results revealed that external support for digitalization is the first step in ensuring digital transformation success among SMEs, while operations technology readiness is the most inaccessible success determinant.Research limitations/implicationsThe study highlights the degree of importance of the 11 success determinants identified, which magnifies each determinant's strategic priority based on its driving power and dependence power. Theorizing the dependent variable of “digital transformation success” and quantitatively measuring the extent to which each success determinant contributes to explaining “digital transformation success” offers an exciting opportunity for future research.Practical implicationsDigital transformation success phenomenon within the Industry 4.0 context is significantly different from the digitalization success concept within the traditional literature. The digital transformation under Industry 4.0 is immensely resource-intensive and complex. Smaller manufacturers must have specific capabilities such as change management and digitalization strategic planning capability to reach a certain degree of information, digital, operations and cyber maturity.Originality/valueThe digital transformation success guide developed in the study describes each success determinants' functionality in relation to other determinants and explains how they might contribute to the digital transformation success within the manufacturing sector. This guide enables smaller manufacturers to better understand the concept of manufacturing digital transformation under Industry 4.0 and devise robust strategies to steer their digital transformation process effectively.

Investigations on tensile fractography and wear characteristics of Al7075-Al2O3-SiC Hybrid Metal Matrix Composites routed through liquid metallurgical techniques

The Al2O3-SiC reinforced Al7075 Metal Matrix Composite (MMCs) is fabricated through liquid metallurgical technique. Ceramic particulates were amalgamated into aluminium alloy to achieve improved mechanical properties and wear resistance. Al-7075/Al2O3/SiC hybrid MMCs were produced by reinforcing 2%, 3%, 4% and 5% of Al2O3 and 3%, 5% and 7% of SiC particles. Microstructural analysis was carried out to evaluate the uniform dispersal of reinforcing particulates within the base matrix. The output results indicate that the mechanical properties of the hybrid MMCs enhanced by increase the wt. % of ceramic particulates. Tensile fractography results show the internal fracture structure of the tensile test specimens in which the particulates fracture and pullouts were observed. The wear characteristics of developed composites are studied using pin on disc apparatus. The high wear resistance is observed at 5% Al2O3 + 7% SiC reinforced MMCs.