Wanying Liu, Junjie Yang, Yuhong Qiu, Ying Liu and Kuanhai Deng
The preferable concentration of titanium carbide was optimized and added as an additive to the micro-arc oxidation electrolyte to produce a high corrosion-resistant coating on…
Abstract
Purpose
The preferable concentration of titanium carbide was optimized and added as an additive to the micro-arc oxidation electrolyte to produce a high corrosion-resistant coating on D16T aluminum alloy.
Design/methodology/approach
Ceramic coatings were deposited on D16T aluminum alloy by plasma electrolytic oxidation in alkaline silicate electrolytes with micron titanium carbide particle suspending at different concentrations. Influences of additive concentration on morphology, elemental and phase composition and corrosion resistance of doped PEO coatings were evaluated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and electrochemical methods, respectively.
Findings
Results revealed that suspending titanium carbide additives incorporated into ceramic coatings through discharging channels and chemically transformed into amorphous stage. The content of titanium in the doped coatings increased with the increasing concentration of suspending micron additive. Compared with the coating without particle addition, the corrosion resistance of the coating produced in 8 g/L titanium carbide suspension increased more than 20 times. The result indicated that the incorporation of titanium into the PEO coatings formed on the D16T aluminum alloy could effectively improve the corrosion resistance.
Originality/value
The mechanism of corporation of TiC and the mechanism of improving the corrosion resistance of the coating were proposed.
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Melis Attar and Aleem Abdul-Kareem
The prevalence of crises is a real phenomenon that demands proper planning and implementation of measures to preempt and curb its consequences on both national economies and…
Abstract
The prevalence of crises is a real phenomenon that demands proper planning and implementation of measures to preempt and curb its consequences on both national economies and business operations. Crisis is one of the concepts that cannot be overlooked, pervasive in nature, and does not necessarily denote negativity. Crisis is no longer an unusual, arbitrary, or minor characteristic of today's business environment. As far as the business environment continues to be volatile and unpredictable, it is unlikely that business organizations would be free from crises. Crises are noted to be a vital part of a business context and can serve as an avenue for positive change and creativity if the right tools and techniques are employed to properly manage them. On the other hand, crises can jeopardize the continued existence of the organization and obstruct the achievement of its goals. Thus, the debilitating ramifications of crises on business growth, survival and overall success calls for adoption of sustainable crisis management approaches in this new business world order that is framed by Industry 5.0, digitalization, and green business practices. The primary purpose of this article is to establish how modern crisis management methods could lead to sustainable organizational development. The current study departs from existing studies in the literature by systematically presenting methods to anticipate, solve, and transform business crises into advantage. The chapter also throws light on how organizations should manage business crises that may well be accelerated by Industry 5.0 and its components; digitalization and sustainable development.
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Sareh Götelid, Taoran Ma, Christophe Lyphout, Jesper Vang, Emil Stålnacke, Jonas Holmberg, Seyed Hosseini and Annika Strondl
This study aims to investigate additive manufacturing of nickel-based superalloy IN718 made by powder bed fusion processes: powder bed fusion laser beam (PBF-LB) and powder bed…
Abstract
Purpose
This study aims to investigate additive manufacturing of nickel-based superalloy IN718 made by powder bed fusion processes: powder bed fusion laser beam (PBF-LB) and powder bed fusion electron beam (PBF-EB).
Design/methodology/approach
This work has focused on the influence of building methods and post-fabrication processes on the final part properties, including microstructure, surface quality, residual stresses and mechanical properties.
Findings
PBF-LB produced a much smoother surface. Blasting and shot peening (SP) reduced the roughness even more but did not affect the PBF-EB surface finish as much. As-printed PBF-EB parts have low residual stresses in all directions, whereas it was much higher for PBF-LB. However, heat treatment removed the stresses and SP created compressive stresses for samples from both PBF processes. The standard Arcam process parameter for PBF-EB for IN718 is not fully optimized, which leads to porosity and inferior mechanical properties. However, impact toughness after hot isostatic pressing was surprisingly high.
Originality/value
The two processes gave different results and also responses to post-treatments, which could be of advantage or disadvantage for different applications. Suggestions for improving the properties of parts produced by each method are presented.
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Mustafa Kuntoğlu, Emin Salur, Munish Kumar Gupta, Saad Waqar, Natalia Szczotkarz, Govind Vashishtha, Mehmet Erdi Korkmaz and Grzegorz M. Krolczyk
The nickel-based alloys Inconel 625 and Inconel 718 stand out due to their high strength and corrosion resistance in important industries like aerospace, aviation and automotive…
Abstract
Purpose
The nickel-based alloys Inconel 625 and Inconel 718 stand out due to their high strength and corrosion resistance in important industries like aerospace, aviation and automotive. Even though they are widely used, current techniques of producing materials that are difficult to cut pose several problems from a financial, ecological and even health perspective. To handle these problems and acquire improved mechanical and structural qualities, laser powder bed fusion (LPBF) has been widely used as one of the most essential additive manufacturing techniques. The purpose of this article is to focus on the state of the art on LPBF parts of Inconel 625 and Inconel 718 for microstructure, mechanical behavior and postprocessing.
Design/methodology/approach
The mechanical behavior of LPBF-fabricated Inconel is described, including hardness, surface morphology and wear, as well as the influence of fabrication orientation on surface quality, biocompatibility and resultant mechanical properties, particularly tensile strength, fatigue performance and tribological behaviors.
Findings
The postprocessing techniques such as thermal treatments, polishing techniques for surface enhancement, mechanical and laser-induced peening and physical operations are summarized.
Originality/value
The highlighted topic presents the critical aspects of the advantages and challenges of the LPBF parts produced by Inconel 718 and 625, which can be a guideline for manufacturers and academia in practical applications.
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Yong Cheng, Zhongxu Xiao, Haihong Zhu, Xiaoyan Zeng and Guoqing Wang
Selective laser melting (SLM) is a promising additive manufacturing technology in the field of complex parts’ fabrication. High temperature gradient and residual stress are vital…
Abstract
Purpose
Selective laser melting (SLM) is a promising additive manufacturing technology in the field of complex parts’ fabrication. High temperature gradient and residual stress are vital problems for the development of SLM technology. The purpose of this paper is to investigate the influence of substrate characteristics on the residual stress of SLMed Inconel 718 (IN718).
Design/methodology/approach
The SLMed IN718 samples were fabricated on the substrates with different characteristics, including pre-compression stress, materials and pre-heating. The residual stress at the center of the top surface was measured and compared through Vickers micro-indentation.
Findings
The results indicate that the residual stress reduces when the substrate contains pre-compression stress before the SLM process starts. Both substrate thermal expansion coefficient and thermal conductivity affect the residual stress. In addition to reducing the difference of thermal expansion coefficient between the substrate and the deposited material, the substrate with low thermal conductivity can also decrease the residual stress. Substrate pre-heating at 150°C reduces nearly 42.6 per cent residual stress because of the reduction of the temperature gradient.
Originality/value
The influence of substrate characteristics on the residual stress has been studied. The investigation results can help to control the residual stress generated in SLM processing.
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Qiqiang Cao, Jiong Zhang, Shuai Chang, Jerry Ying Hsi Fuh and Hao Wang
This study aims to further the understanding of support structures and the likely impacts on maraging steel MS1 parts fabricated by selective laser melting (SLM) at 45°, 60° and…
Abstract
Purpose
This study aims to further the understanding of support structures and the likely impacts on maraging steel MS1 parts fabricated by selective laser melting (SLM) at 45°, 60° and 75° building angles.
Design/methodology/approach
Two groups of samples, one group with support structures and the other group without support structures, were designed with the same specifications and printed under the same conditions by SLM at 45°, 60° and 75° building angles. Differences in dimensional accuracy, surface roughness, Vickers microhardness, residual stress and microstructure were compared between groups.
Findings
The results showed that with support structures, more accurate dimension and slightly higher Vickers microhardness could be obtained. Larger compressive stress dominated and was more uniformly distributed on the supporting surface. Without support structures, the dimension became more precise as the building angle increased and alternating compressive and tensile stress was unevenly distributed on the supporting surface. In addition, the surface roughness of the outer surface decreased with the increase of the built angle, regardless of the support structures. Furthermore, whether the building angle was 45°, 60° or 75°, the observed microstructures revealed that the support structures altered the orientation of the molten pool and the direction of grain growth.
Originality/value
This paper studies the influence of support structures on the workpieces printed at different building angles. Support structures affect the residual stress distribution, heat dissipation rate and microstructure of the parts, and thus affecting the printing quality. Therefore, it is necessary to balance the support strategy and printing quality to better apply or design the support structures in SLM.
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Yuan-Jian Yang, Guihua Wang, Qiuyang Zhong, Huan Zhang, Junjie He and Haijun Chen
Gas pipelines are facing serious risk because of the factors such as long service life, complex working condition and most importantly, corrosion. As one of the main failure…
Abstract
Purpose
Gas pipelines are facing serious risk because of the factors such as long service life, complex working condition and most importantly, corrosion. As one of the main failure reasons of gas pipeline, corrosion poses a great threat to its stable operation. Therefore, it is necessary to analyze the reliability of gas pipelines with corrosion defect. This paper uses the corresponding methods to predict the residual strength and residual life of pipelines.
Design/methodology/approach
In this paper, ASME-B31G revised criteria and finite element numerical analysis software are used to analyze the reliability of a special dangerous section of a gas gathering pipeline, and the failure pressure and stress concentration of the pipeline under three failure criteria are obtained. Furthermore, combined with the predicted corrosion rate of the pipeline, the residual service life of the pipeline is calculated.
Findings
This paper verifies the feasibility of ASME-B31G revised criteria and finite element numerical analysis methods for reliability analysis of gas pipelines with corrosion defect. According to the calculation results, the maximum safe internal pressure of the pipeline is 9.53 Mpa, and the residual life of the pipeline under the current operating pressure is 38.41 years, meeting the requirements of safe and reliable operation.
Originality/value
The analysis methods and analysis results provide reference basis for the reliability analysis of corroded pipelines, which is of great practical engineering value for the safe and stable operation of natural gas pipelines.
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Yogesh Patil, Ashik Kumar Patel, Gopal Dnyanba Gote, Yash G. Mittal, Avinash Kumar Mehta, Sahil Devendra Singh, K.P. Karunakaran and Milind Akarte
This study aims to improve the acceleration in the additive manufacturing (AM) process. AM tools, such as extrusion heads, jets, electric arcs, lasers and electron beams (EB)…
Abstract
Purpose
This study aims to improve the acceleration in the additive manufacturing (AM) process. AM tools, such as extrusion heads, jets, electric arcs, lasers and electron beams (EB), experience negligible forces. However, their speeds are limited by the positioning systems. In addition, a thin tool must travel several kilometers in tiny motions with several turns while realizing the AM part. Hence, acceleration is a more significant limiting factor than the velocity or precision for all except EB.
Design/methodology/approach
The sawtooth (ST) scanning strategy presented in this paper minimizes the time by combining three motion features: zigzag scan, 45º or 135º rotation for successive layers in G00 to avoid the CNC interpolation, and modifying these movements along 45º or 135º into sawtooth to halve the turns.
Findings
Sawtooth effectiveness is tested using an in-house developed Sand AM (SaAM) apparatus based on the laser–powder bed fusion AM technique. For a simple rectangle layer, the sawtooth achieved a path length reduction of 0.19%–1.49% and reduced the overall time by 3.508–4.889 times, proving that sawtooth uses increased acceleration more effectively than the other three scans. The complex layer study reduced calculated time by 69.80%–139.96% and manufacturing time by 47.35%–86.85%. Sawtooth samples also exhibited less dimensional variation (0.88%) than zigzag 45° (12.94%) along the build direction.
Research limitations/implications
Sawtooth is limited to flying optics AM process.
Originality/value
Development of scanning strategy for flying optics AM process to reduce the warpage by improving the acceleration.
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Hualong Yang, Zhiying Cheng and Junjie Zhou
The online profile picture of a doctor serves as a pivotal source of visual information, playing a key role in shaping the doctor’s professionalism in the online health market…
Abstract
Purpose
The online profile picture of a doctor serves as a pivotal source of visual information, playing a key role in shaping the doctor’s professionalism in the online health market. Doctors can strategically curate the elements of their online profile pictures, such as attire and background, to either reinforce a formal image or craft a casual image, thereby influencing patients’ doctor choices. Despite this, the relative effectiveness of formal or casual images in swaying patient choices remains unclear. This study endeavors to bridge this knowledge gap.
Design/methodology/approach
This study tested the influence of a doctor’s attire and background in their profile picture on patient decision-making, with a focus on discerning variations in impact among patient groups differentiated by the severity of their illnesses (i.e. high-severity versus low-severity conditions). We formulated four hypotheses and tested them through an econometric analysis and a controlled laboratory experiment.
Findings
The empirical findings reveal that doctors’ formal profile pictures, characterized by formal attire and backgrounds, exert a more pronounced influence on patient choices than casual images. The severity of a patient’s illness positively moderated the relationship between formal images and patient choices.
Originality/value
These insights make a significant contribution to the understanding of patient behavior in selecting doctors within the online health market. Furthermore, they offer valuable guidance for doctors in optimizing their online profile presentation to better align with patient preferences and expectations.
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Yahui Liu, Hualu Zheng, Shuai Yang and Junjie Wang
This study aims to examine how the effect of pop-ups on an omnichannel brand’s subsequent online sales is moderated by the brand’s online price and premium promotions, paid search…
Abstract
Purpose
This study aims to examine how the effect of pop-ups on an omnichannel brand’s subsequent online sales is moderated by the brand’s online price and premium promotions, paid search and popularity signaling.
Design/methodology/approach
Using a difference-in-differences approach, this study appraises variations in two similar Chinese apparel brands’ online sales before and after one of the brands’ implementations of its pop-ups and how the brand’s online promotions modify the pop-ups’ effect.
Findings
Unique, interactive pop-ups boost brands’ subsequent online sales. Online price promotions negatively moderate the effect; online premium promotions and paid search positively moderate it. Moreover, the product’s popularity diminishes the extent to which a pop-up stimulates online demand. These findings can be partially generalized to other categories, such as utilitarian products.
Practical implications
Only certain online strategies enhance the effect of pop-ups on brands’ online sales, so practitioners should strategically select appropriate promotion combinations when they operate pop-ups and allocate resources across channels. In addition, the moderating influence of online promotions on pop-ups depends on the type of product being promoted.
Originality/value
Pop-ups offer proven abilities to deliver sensory experiences to online shoppers, reinforce brand awareness and loyalty and boost online sales. This study extends prior research by examining how various online promotions moderate pop-ups’ effects.