Browsing by Author "Alqahtani, Ibrahim"

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    Coupled effects of temperature and humidity on fracture toughness of Al–Mg–Si–Mn alloy
    (MDPI, 2023-05-30) Alqahtani, Ibrahim; Starr, Andrew; Khan, Muhammad
    The combined effect of temperature and humidity on the fracture toughness of aluminium alloys has not been extensively studied, and little attention has been paid due to its complexity, understanding of its behaviour, and difficulty in predicting the effect of the combined factors. Therefore, the present study aims to address this knowledge gap and improve the understanding of the interdependencies between the coupled effects of temperature and humidity on the fracture toughness of Al–Mg–Si–Mn alloy, which can have practical implications for the selection and design of materials in coastal environments. Fracture toughness experiments were carried out by simulating the coastal environments, such as localised corrosion, temperature, and humidity, using compact tension specimens. The fracture toughness increased with varying temperatures from 20 to 80 °C and decreased with variable humidity levels between 40% and 90%, revealing Al–Mg–Si–Mn alloy is susceptible to corrosive environments. Using a curve-fitting approach that mapped the micrographs to temperature and humidity conditions, an empirical model was developed, which revealed that the interaction between temperature and humidity was complex and followed a nonlinear interaction supported by microstructure images of SEM and collected empirical data.
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    Experimental and theoretical aspects of crack assisted failures of metallic alloys in corrosive environments – a review
    (Elsevier, 2022-09-08) Alqahtani, Ibrahim; Starr, Andrew; Khan, Muhammad
    Failure analysis is one of the complex tasks in engineering materials since it involves analyses of the interdependency of factors like environmental conditions, materials properties and loading conditions etc., causing catastrophic failure of engineering components in real-time applications. In recent times, the advances in characterization techniques have led to the precise findings of the cause of the failures in several cases. However, specific failure analysis-based case studies report that the couple load effects of two or more parameters influencing the failures of engineering components are complex to identify. Moreover, it is difficult to formulate a mathematical model involving the interdependency factors to study the failure behaviour of the engineering materials. Especially in aerospace industry, the crack initiation and propagation in metallic alloys are more complex since the various factors like environmental conditions combined with loading parameters cause unpredictable failures. Hence, there is a need to study the effect of environmental conditions combined with different loading systems on the crack propagation of metallic alloys. The review concludes that still a comprehensive analytical modelling approach is required to relate the interdependencies of couple loads such as humidity and temperature of metallic alloys in corrosive environment.
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    Fracture behaviour of aluminium alloys under coastal environmental conditions: a review
    (MDPI, 2024-03-15) Alqahtani, Ibrahim; Starr, Andrew; Khan, Muhammad
    Aluminium alloys have been integral to numerous engineering applications due to their favourable strength, weight, and corrosion resistance combination. However, the performance of these alloys in coastal environments is a critical concern, as the interplay between fracture toughness and fatigue crack growth rate under such conditions remains relatively unexplored. This comprehensive review addresses this research gap by analysing the intricate relationship between fatigue crack propagation, fracture toughness, and challenging coastal environmental conditions. In view of the increasing utilisation of aluminium alloys in coastal infrastructure and maritime industries, understanding their behaviour under the joint influences of cyclic loading and corrosive coastal atmospheres is imperative. The primary objective of this review is to synthesise the existing knowledge on the subject, identify research gaps, and propose directions for future investigations. The methodology involves an in-depth examination of peer-reviewed literature and experimental studies. The mechanisms driving fatigue crack initiation and propagation in aluminium alloys exposed to saltwater, humidity, and temperature variations are elucidated. Additionally, this review critically evaluates the impact of coastal conditions on fracture toughness, shedding light on the vulnerability of aluminium alloys to sudden fractures in such environments. The variability of fatigue crack growth rates and fracture toughness values across different aluminium alloy compositions and environmental exposures was discussed. Corrosion–fatigue interactions emerge as a key contributor to accelerated crack propagation, underscoring the need for comprehensive mitigation strategies. This review paper highlights the pressing need to understand the behaviour of aluminium alloys under coastal conditions comprehensively. By revealing the existing research gaps and presenting an integrated overview of the intricate mechanisms at play, this study aims to guide further research and engineering efforts towards enhancing the durability and safety of aluminium alloy components in coastal environments.
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    Fracture toughness investigation of AL6082-T651 alloy under corrosive environmental conditions
    (Trans Tech Publications, 2024-04-03) Alqahtani, Ibrahim; Starr, Andrew; Khan, Muhammad
    The crack initiation and propagation in an aluminium alloy in a corrosive environment are complex because of the loading parameters and material properties, which may result in a sudden failure in real-time applications. This paper investigates the fracture toughness of aluminium alloy under varying environmental and corrosion conditions. The main objective of the work is to link the interdependencies of humidity and temperature for an AL6082-T651 alloy in a corrosive environment. This study investigates AL6082-T651alloy's fracture behaviour and mechanism through microstructure and fractographic studies. The results show that a non-corroded sample, at room conditions, provided more load-carrying capacity than a corroded sample. Additionally, an increase in temperature improves fracture toughness, while an increase in humidity results in a decrease in fracture toughness.