Mohammed Fahad and Bavanish B.
Aviation field requires a material with greater tribological characteristics to withstand the critical climate conditions. Hence, it is of paramount importance to enhance the wear…
Abstract
Purpose
Aviation field requires a material with greater tribological characteristics to withstand the critical climate conditions. Hence, it is of paramount importance to enhance the wear resistance of material. AZ91D magnesium alloy is a light weight material used in the aviation field for the construction work. The purpose of this study is to augment the wear properties of AZ91D alloy by reinforcing with hard particles such as tungsten carbide (WC) and silicon dioxide (SiO2).
Design/methodology/approach
In this work, three types of composites were fabricated, namely, AZ91D – WC, AZ91D – SiO2 and AZ91D – (WC + SiO2) by ball milling method, and the tribological properties were analyzed using pin-on-disc apparatus.
Findings
Results showed that the hardness of AZ91D alloy was greatly improved due to the reinforcing effects of WC and SiO2 particles. Wear study showed that wear rate of AZ91D alloy and its composites increased with the increase of applied load due to ploughing effect and decreased with the increase of sliding speed owing to the formation of lubricating tribolayer. Further, the AZ91D – (WC + SiO2) composite exhibited the lower wear rate of 0.0017 mm3/m and minimum coefficient of friction of 0.33 at a load of 10 N and a sliding speed of 150 mm/s due to the inclusion of hybrid WC and SiO2 particles. Hence, the proposed AZ91D – (WC + SiO2) composite could be a suitable candidate to be used in the aviation applications.
Originality/value
This work is original which deals with the effect of hybrid particles, i.e. WC and SiO2 on the wear performance of the AZ91D magnesium alloy composites. The literature review showed that none of the studies focused on the reinforcement of AZ91D alloy by the combination of carbide and metal oxide particles as used in this investigation.
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Mohammed Fahad and Bavanish B.
The aviation field requires a material with the ability to withstand severe environmental conditions. The purpose of this paper is to provide higher wear resistance and improve…
Abstract
Purpose
The aviation field requires a material with the ability to withstand severe environmental conditions. The purpose of this paper is to provide higher wear resistance and improve the lifetime of aircraft. Hence, it is vital to enhance the wear resistance and strength of the material.
Design/methodology/approach
In this investigation, the Az91D magnesium alloy was reinforced with lanthanum (La2O3) and cerium oxide (CeO2) nanoparticles by stir casting and heat treatment process and the tribological and mechanical properties were analyzed.
Findings
The results showed the Az91D/CeO2 composite exhibited higher density (1.96 g/cm3) and lower porosity (1.01%) compared to other materials due to the diffusion of CeO2 nanoparticles in between the atoms of Az91D alloy. The hardness of Az91D/ CeO2 & Az91D/ La2O3 was improved by 38% and 34%, respectively, compared to Az91D alloy owing to the reinforcing effect of hard nanoparticles. Further, the inclusion of nanoparticles decreased the mass loss and showed lower wear rate compared to the Az91D alloy due to the pinning effect of nanoparticles. In addition, the friction coefficient was observed in the order of Az91D > Az91D/ La2O3 > Az91D/ CeO2. Moreover, the heat treatment displayed positive results on the properties of all the materials.
Originality/value
This work is original as the combination of cerium oxide nanoparticles with Az91D magnesium alloy is not tried by earlier investigators. Further, the comparative performance of both lanthanum and cerium oxide nanoparticles on the tribological and mechanical behavior of Az91D alloy has been analyzed for aviation application. This study will provide new information to the scientific world to increase the lifetime of aviation structures.
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Bismark Osei, Agbemavor Korsi Fiagbe and Evans Kulu
This study aims to examine the appropriate measures needed toward achieving sustainability of renewable energy production among developing and middle-income countries.
Abstract
Purpose
This study aims to examine the appropriate measures needed toward achieving sustainability of renewable energy production among developing and middle-income countries.
Design/methodology/approach
This study uses semi-annual panel data covering the period 2000–2020 among 152 developing and middle-income countries and Cox proportional hazard model for the analysis.
Findings
Estimates indicate that effective operations of environmental institutions, investment in research and development, subsidizing the production of renewable energy, government investment in producing renewable energy and investment in renewable energy production made by the private sector will contribute immensely toward achieving sustainability of renewable energy production.
Practical implications
This study recommends that governments should rationalize their expenditures to mobilize enough resources for investment in renewable energy production. Again, operations of environmental institutions should be enhanced through giving their managers’ performance contracts and licensing its employees. Enabling environment should be created for private sector to increase their investment in renewable energy production.
Originality/value
Empirical studies have been carried out exploring measures to deal with climate change. Nonetheless, the appropriate measures needed toward achieving sustainability of renewable energy production among developing and middle-income countries have not been explored in existing empirical studies. Hence, this study fills the gap in existing empirical studies.
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Sivaselvan S., Natarajan M., Devadasan S.R. and Sivaram N.M.
Aluminum alloys are applicable in marine and aero fields. Alloys AA5083 and AA6061 are aluminum alloys with different chemical and physical properties. Combination of two…
Abstract
Purpose
Aluminum alloys are applicable in marine and aero fields. Alloys AA5083 and AA6061 are aluminum alloys with different chemical and physical properties. Combination of two dissimilar materials could result in enhanced strength. Generally, dissimilar aluminum alloy joint is made by friction stir welding (FSW) to achieve improved physical properties compared with the parent alloys. The purpose of this research is to develop a new FSW dissimilar material with enhanced properties using AA5083 and AA6061 alloys.
Design/methodology/approach
In this research, FSW joint was made for butt joint configuration using AA5083 and AA6061 aluminum alloys. Cylindrical pin with threaded profile was used to perform the joint. The tool tilting angle was maintained as constant, and the tool rotational speed and the welding speed were varied. Wear performance and mechanical strength of the joint were analyzed.
Findings
The results revealed that the increase of tool rotational speed led to poor wear performance, whereas increase of welding speed showed a better wear performance. Further, the prepared joint was analyzed for different wear parameters such as sliding velocity and applied load. The results displayed that the increase of sliding velocity exhibited low wear rate and the increase of load showed high wear rate.
Originality/value
This work is original and deals with the wear performance of AA5083–AA6061 joint at different tool rotational and welding speeds.