Effects of electrolysis on magnetic abrasive finishing of AA6063-T1 tube internal surface using combination machining tool

In this research, we studied the effects of electrolysis in the magnetic abrasive finishing of an AA6063-T1 tube internal surface. The finishing surface‘s hairline morphology was removed in a short time by physical characteristic transformation of the finishing surface in which the aluminum oxide film was formed during the electrolysis. Next, magnetic abrasive finishing was used to eliminate the oxidation layer and polish the surface to a mirror-finishing standard. The two-step process effectively improved the surface roughness in a shorter time. The morphology changes before and after the finishing process, was studied by surface roughness measurement and scanning electron microscope photographs. Notably, the pit or micro holes formation during the electrolysis on the aluminum oxide film was examined and its effect on the surface roughness was studied. The elements’ residual on the surface was investigated by X-ray photoelectron spectroscopy analyzer before and after the process to confirm the formation and removal of oxidation film on the finishing surface. The lower value for torque measurement in electrolysis combined process compared to the conventional method was due to the porous characteristic of aluminum oxide film

N95 respirator hybrid decontamination method using Ultraviolet Germicidal Irradiation (UVGI) coupled with Microwave-Generated Steam (MGS).

The Coronavirus Disease 2019 (COVID-19) pandemic has induced a critical supply of personal protective equipment (PPE) especially N95 respirators. Utilizing respirator decontamination procedures to reduce the pathogen load of a contaminated N95 respirator can be a viable solution for reuse purposes. In this study, the efficiency of a novel hybrid respirator decontamination method of ultraviolet germicidal irradiation (UVGI) which utilizes ultraviolet-C (UV-C) rays coupled with microwave-generated steam (MGS) against feline coronavirus (FCoV) was evaluated. The contaminated 3M 1860 respirator pieces were treated with three treatments (UVGI-only, MGS-only, and Hybrid-UVGI + MGS) with variable time. The virucidal activity was evaluated using the TCID50 method. The comparison of decontamination efficiency of the treatments indicated that the hybrid method achieved at least a pathogen log reduction of 4 logs, faster than MGS and UVGI. These data recommend that the proposed hybrid decontamination system is more effective comparatively in achieving pathogen log reduction of 4 logs

Effect of Surface States on Joining Mechanisms and Mechanical Properties of Aluminum Alloy (A5052) and Polyethylene Terephthalate (PET) by Dissimilar Friction Spot Welding

In this research, polyethylene terephthalate (PET), as a high-density thermoplastic sheet, and Aluminum A5052, as a metal with seven distinct surface roughnesses, were joined by friction spot welding (FSW). The effect of A5052’s various surface states on the welding joining mechanism and mechanical properties were investigated. Friction spot welding was successfully applied for the dissimilar joining of PET thermoplastics and aluminum alloy A5052. During FSW, the PET near the joining interface softened, partially melted and adhered to the A5052 joining surface. The melted PET evaporated to form bubbles near the joining interface and cooled, forming hollows. The bubbles have two opposite effects: its presence at the joining interface prevent PET from contacting with A5052, while bubbles or hollows are crack origins that induce crack paths which degrade the joining strength. On the other hand, the bubbles’ flow pushed the softened PET into irregularities on the roughened surface to form mechanical interlocking, which significantly improved the strength. The tensile-shear failure load for an as-received surface (0.31 μ m Ra) specimen was about 0.4–0.8 kN while that for the treated surface (>0.31 μ m Ra) specimen was about 4.8–5.2 kN

A review on friction stir butt welding of aluminum with magnesium: A new insight on joining mechanisms by interfacial enhancement

The growing demand for lightweight materials in the automotive and aerospace industries has driven research on joining dissimilar lightweight alloys, particularly Al and Mg alloys (Al/Mg). Friction stir welding (FSW) is a promising technique for joining Al/Mg alloys, as it works below the base metal's melting temperature, leading to refined microstructures, reduced porosity, and enhanced productivity. The strength of Al/Mg friction stir weldment depends on the evolved interface, which is primarily characterized by micromechanical interlocks, type, and intermetallic compounds (IMCs) distribution. Different interfaces for butt joints have been discussed in the literature. However, the mechanism of interfacial interaction together with the ways to enhance the interface have not been reviewed yet. This review article fills the gap by analyzing the retrospective data for process parameters and mechanical properties. Joining mechanisms and the evolution of different interfaces at the microstructural level have been discussed. Lastly, ways to enhance the interface for improved mechanical properties are explained. By offering essential insights into FSW techniques and Al/Mg weld interfaces, this review article paves the way for developing FSW procedures for Al/Mg butt welds aiming for enhanced strength and performance. This review article is expected to be of interest to researchers and engineers working in the field of FSW, particularly for Al/Mg lightweight applications. It provides an overview of the current state of knowledge and identifies key areas for future research

Assessment of fatigue and corrosion fatigue behaviours of the nitrogen ion implanted CpTi

The fatigue and corrosion fatigue behaviours of commercially pure titanium (CpTi) have been particularly studied because the requirements of titanium (Ti) base materials are widely used for biomedical applications. The optimal properties of CpTi surface can be preserved by nitrogen ion implantation at a certain dose and energy. Still the fatigue and corrosion fatigue behaviours of nitrogen ion implanted CpTi (Nii-Ti) must be verified. This study performs the fatigue tests for CpTi and Nii-Ti specimens in a laboratory air and the corrosion fatigue tests for Nii-Ti specimens in a saline solution. Effects of nitrogen ion implantation on surface properties can improve the fatigue strength, fatigue life and corrosion fatigue life of Ti base materials. The corrosion pit growth law has been established on the basis of empirical data for predicting the corrosion penetration rate to estimate to the service life of Nii-Ti

Formation and influencing mechanism of the intermetallic compound in the friction stir welding of immiscible AZ31 and SPHC steel using aluminium powder as an additive

The primary issue with joining an immiscible magnesium/iron system is the lack of a bonding medium. This research used an aluminium (Al) additive as a bonding medium to facilitate the formation of an interface layer. Immiscible AZ31 magnesium alloy and SPHC low-carbon steel were successfully joined by employing aluminium (Al) powder as an additive in the gap between them with friction stir welding (FSW). The extensive interfacial microstructural analyses confirmed that the aluminium-rich Fe2Al5 intermetallic compound (IMC) formed with a range of 20–25 nm in thickness at the interface between magnesium and iron resulted from the metallurgical reaction between the Al powder additive and base SPHC steel. This IMC phase served as a transitional layer, facilitating the metallurgical bonding between Magnesium and Iron. The tensile strength of the joint was significantly improved by 43%, from 126 MPa without the additive to 180 MPa using the aluminium additive. The formation of the following well-matched interface lattice sites between Fe and Fe2Al5 region was identified: (002)Fe2Al5//(110)Fe, [110]Fe2Al5//[1‾ 13]Fe. The intermetallic Fe2Al5 was composed of nanocrystalline and amorphous interface layers. Furthermore, the fracture of the joint occurred at the interface, indicating a brittle mode of fracture behaviour

Integrated approach to Wire Arc Additive Manufacturing (WAAM) optimization: Harnessing the synergy of process parameters and deposition strategies

The flexibility of Additive Manufacturing (AM) technologies in the metal 3D printing process has gained significant attention in research and industry, which allows for fabricating complicated and intricate Near-Net-Shape (NNS) geometry designs. The achievement of desired characteristics in Wire-Arc Additive Manufactured (WAAM) components is primarily contingent upon the careful selection and precise control of significant processing variables, including bead deposition strategy, wire materials, type of heat source, wire feed speed, and the application of shielding gas. As a result, optimizing these most significant process parameters has improved, producing higher-quality WAAM-manufactured components. Consequently, this has contributed to the overall rise in the method's popularity and many applications. This article aims to provide an overview of the wire deposition strategy and the optimization of process parameters in WAAM. The optimization of numerous wire deposition techniques and process parameters in the WAAM method, which is required to manufacture high-quality additively manufactured metal parts, is summarised. The WAAM optimization algorithm, in addition to anticipate technological developments, has been proposed. Subsequently, a discussion ensues regarding the potential for WAAM optimization within the swiftly growing domain of WAAM. In the end, conclusions have been derived from the reviewed research work

Decontamination Methods of N95 Respirators Contaminated with SARS-CoV-2

In the preparation and response to the COVID-19 pandemic, a sufficient supply of personal protective equipment (PPE), particularly the face mask, is essential. Shortage of PPE due to growing demand leaves health workers at significant risk as they fight this pandemic on the frontline. As a mitigation measure to overcome potential mask shortages, these masks could be decontaminated and prepared for reuse. This review explored past scientific research on various methods of decontamination of the N95-type respirators and their efficiency against the SARS-CoV-2 virus. Ultraviolet germicidal irradiation (UVGI) and hydrogen peroxide vapor (HPV) show great potential as an effective decontamination system. In addition, UVGI and HPV exhibit excellent effectiveness against the SARS-CoV-2 virus on the N95 respirator surfaces

Friction stir alloying of AZ61 and mild steel with Cu-CNT additive

Dissimilar joining between lightweight magnesium (Mg) alloys and steel is essential to produce lighter vehicles, improve vehicles’ fuel efficiency, and reduce carbon emissions. However, the joining of Mg to steel is impractical due to the immiscible properties between these metals. In this experiment, friction stir alloying (FSA) is proposed to solve this problem. The additive, consisting of different wt% of carbon nanotubes (CNT) in Cu powder was first added into the gap between the workpieces and then friction stir welding (FSW) was performed at varied traverse speed and constant rotational speed. After the joining, microstructure characteristics and mechanical properties of Cu-CNT reinforced Mg/steel joints were investigated. Transmission electron microscopy (TEM) analysis of the Mg/steel joint revealed the formation of IMC at the interface of the joint. Further analysis by X-ray diffraction (XRD) showed a dominant presence of Mg2Cu IMC which indicated the interdiffusion of Cu into Mg element to establish intermetallic bonding. The presence of CNT inside the Mg matrix was also confirmed by TEM which contributed to the strengthening effect of the joint. Tensile and microhardness results revealed a notable enhancement of joint mechanical properties when Cu-CNT additive was added as compared to specimens with only Cu additive, and specimens without additive. The enhanced tensile strength and microhardness of the Cu-CNT reinforced Mg/steel joint was attributed to the dispersion of CNT inside the Mg matrix, which induced multiple dislocations in the surface region, therefore improving the mechanical properties of the joint