Development of Metal Matrix Composites suitable for hulls and ship decks

Abstract

Metal matrix composites (MMCs) have gained significant attention due to their enhanced mechanical and tribological properties, making them suitable for various industrial applications, particularly in the marine and aerospace sectors. However, challenges such as poor reinforcement dispersion, porosity, and limited optimization of processing parameters remain critical research gaps. While extensive studies have been conducted on aluminiumbased MMCs, limited research exists on AA5083-H111 reinforced with coal, particularly in the context of friction stir processing (FSP) as a fabrication method. This study aimed to fabricate aluminium metal matrix composites (AMMCs) of AA5083-SiC and AA5083-Coal MMCs using FSP for potential application in ship hulls and decks, focusing on reinforcing the joint region rather than fabricating a bulk MMC sheet. The novelty of this research lies in the use of coal as an alternative reinforcement, offering a cost-effective and sustainable approach to MMC fabrication while maintaining high wear resistance and mechanical strength. Silicon carbide (SiC) was used as a benchmark reinforcement due to its well-documented ability to improve hardness, wear resistance, and thermal stability, providing a comparative reference for evaluating the effectiveness of coal as a reinforcement material. In the fabrication process, AA5083-H111 was reinforced with silicon carbide and coal particles to create AMMCs, and their properties were compared to unreinforced AA5083-H111. To run the test on the AA5083-H111, AA5083/SiC composite joints and AA5083/Coal composite joints, the specimens were cut with a CNC milling machine. Among the tests performed were tensile testing, macrostructure and microstructure analysis, fractographic analysis (SEM), hardness tests, flexural tests, chemical composition analysis and X-ray diffraction (XRD) analysis. The described specimens for the composites were cut from various positions on the plates, including the plate's start, middle and end. This method enabled a thorough study of material characteristics and behavior by constantly analyzing material properties at these exact places across all testing. The following symbols were used to represent the cut positions on the processed plates to symbolise their positioning (S for the start, M for the middle and E for the end of the plate).