Investigation of the microstructure, electrical and mechanical properties of Al-CNTs-B4C composite prepared by double-step stir casting for power transmission conductor
Monolithic aluminium alloy is a modern engineering material that is in high demand owing to its excellent performance and versatility. It has a high electrical conductivity, low density, high strength- to- weight ratio, and high resistance to corrosion. However, it lacks adequate resistance to creep...
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IOP Publishing
2024-01-01
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| Online Access: | https://doi.org/10.1088/2053-1591/ad8e30 |
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| author | Uchenna Ifeanyi Malobi Ikechukwu Ike-Eze C Ezema Chika Oliver Ujah |
| author_facet | Uchenna Ifeanyi Malobi Ikechukwu Ike-Eze C Ezema Chika Oliver Ujah |
| author_sort | Uchenna Ifeanyi Malobi |
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| description | Monolithic aluminium alloy is a modern engineering material that is in high demand owing to its excellent performance and versatility. It has a high electrical conductivity, low density, high strength- to- weight ratio, and high resistance to corrosion. However, it lacks adequate resistance to creep, fatigue, stable microstructure, and strength at elevated temperatures. To overcome these deficiencies, aluminium matrix composites are developed. This work focuses on an experimental investigation of the microstructure, mechanical strength, and electrical conductivity of Al-CNTs-B _4 C composite consolidated by a double-step stir casting technique. An x-ray diffractometer, transmission electron microscopy, and a field-emission scanning electron microscope fitted with energy dispersive x-ray spectroscopy were used to characterize the start-up powders and the cast samples. A Brinell tester was used to measure the microhardness of the cast samples. A four-point probe meter was used to determine the electrical conductivity. The microstructural results revealed formation of Al _4 C _3 and Al _3 BC intermetallics, B _4 C phase and amorphous carbon precipitate. Marginally improved electrical conductivity of 33.33 × 10 ^7 S m ^−1 (65.1% IACS) was obtained with Al-5CNTs-15B _4 C, together with high microhardness of 725.72 MPa. The microhardness improved by 94.7% over monolithic pure Al. The double-step stir casting enhanced the homogenous dispersion of the reinforcements. The improvements in the mechanical properties and electrical conductivity were attributed to the synergy between B _4 C and CNTs which induced Orowan looping, load transfer effect, plastic deformation and dislocation pinning in the composite. It is recommended that this composite will perform creditably in power transmission. |
| format | Article |
| id | doaj-art-3a7360d58dd34c43b43cfedc92fcdd23 |
| institution | Kabale University |
| issn | 2053-1591 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Materials Research Express |
| spelling | doaj-art-3a7360d58dd34c43b43cfedc92fcdd232024-11-11T13:16:34ZengIOP PublishingMaterials Research Express2053-15912024-01-01111111560210.1088/2053-1591/ad8e30Investigation of the microstructure, electrical and mechanical properties of Al-CNTs-B4C composite prepared by double-step stir casting for power transmission conductorUchenna Ifeanyi Malobi0https://orcid.org/0009-0006-0437-3981Ikechukwu Ike-Eze C Ezema1https://orcid.org/0000-0002-5237-1562Chika Oliver Ujah2https://orcid.org/0000-0002-9713-3023Africa Centre of Excellence for Sustainable Power and Energy Development, University of Nigeria , Nsukka, NigeriaAfrica Centre of Excellence for Sustainable Power and Energy Development, University of Nigeria , Nsukka, Nigeria; Department of Metallurgical and Materials Engineering, University of Nigeria , Nsukka, NigeriaAfrica Centre of Excellence for Sustainable Power and Energy Development, University of Nigeria , Nsukka, Nigeria; Department of Mechanical and Industrial Engineering Technology, University of Johannesburg , South AfricaMonolithic aluminium alloy is a modern engineering material that is in high demand owing to its excellent performance and versatility. It has a high electrical conductivity, low density, high strength- to- weight ratio, and high resistance to corrosion. However, it lacks adequate resistance to creep, fatigue, stable microstructure, and strength at elevated temperatures. To overcome these deficiencies, aluminium matrix composites are developed. This work focuses on an experimental investigation of the microstructure, mechanical strength, and electrical conductivity of Al-CNTs-B _4 C composite consolidated by a double-step stir casting technique. An x-ray diffractometer, transmission electron microscopy, and a field-emission scanning electron microscope fitted with energy dispersive x-ray spectroscopy were used to characterize the start-up powders and the cast samples. A Brinell tester was used to measure the microhardness of the cast samples. A four-point probe meter was used to determine the electrical conductivity. The microstructural results revealed formation of Al _4 C _3 and Al _3 BC intermetallics, B _4 C phase and amorphous carbon precipitate. Marginally improved electrical conductivity of 33.33 × 10 ^7 S m ^−1 (65.1% IACS) was obtained with Al-5CNTs-15B _4 C, together with high microhardness of 725.72 MPa. The microhardness improved by 94.7% over monolithic pure Al. The double-step stir casting enhanced the homogenous dispersion of the reinforcements. The improvements in the mechanical properties and electrical conductivity were attributed to the synergy between B _4 C and CNTs which induced Orowan looping, load transfer effect, plastic deformation and dislocation pinning in the composite. It is recommended that this composite will perform creditably in power transmission.https://doi.org/10.1088/2053-1591/ad8e30stir castingmicrostructuremicrohardnessaluminium matrix compositecarbon nanotubeselectrical conductivity |
| spellingShingle | Uchenna Ifeanyi Malobi Ikechukwu Ike-Eze C Ezema Chika Oliver Ujah Investigation of the microstructure, electrical and mechanical properties of Al-CNTs-B4C composite prepared by double-step stir casting for power transmission conductor Materials Research Express stir casting microstructure microhardness aluminium matrix composite carbon nanotubes electrical conductivity |
| title | Investigation of the microstructure, electrical and mechanical properties of Al-CNTs-B4C composite prepared by double-step stir casting for power transmission conductor |
| title_full | Investigation of the microstructure, electrical and mechanical properties of Al-CNTs-B4C composite prepared by double-step stir casting for power transmission conductor |
| title_fullStr | Investigation of the microstructure, electrical and mechanical properties of Al-CNTs-B4C composite prepared by double-step stir casting for power transmission conductor |
| title_full_unstemmed | Investigation of the microstructure, electrical and mechanical properties of Al-CNTs-B4C composite prepared by double-step stir casting for power transmission conductor |
| title_short | Investigation of the microstructure, electrical and mechanical properties of Al-CNTs-B4C composite prepared by double-step stir casting for power transmission conductor |
| title_sort | investigation of the microstructure electrical and mechanical properties of al cnts b4c composite prepared by double step stir casting for power transmission conductor |
| topic | stir casting microstructure microhardness aluminium matrix composite carbon nanotubes electrical conductivity |
| url | https://doi.org/10.1088/2053-1591/ad8e30 |
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