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KARAKTERISTIK SIFAT FISIK DAN MEKANIK PADA KOMPOSIT AL 6063/PKSA+SIC MENGGUNAKAN METODE STIR SQUEEZE CASTING

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Palm oil plays a strategic role in Indonesia’s economy as one of the fastest-growing commodities. However, the increase in production also generates a large amount of solid waste such as empty fruit bunches, shells, fibers, and kernels. This waste has the potential to be reused as an additive material in the production of Aluminium Matrix Composites (AMC). This research aims to optimize palm kernel shell waste, which is rich in SiO₂ content, so that it can be utilized as a reinforcement material in the fabrication of AMC. The study evaluates the role of Palm Kernel Shell Ash (PKSA) and Silicon Carbide (SiC) as reinforcement materials through the stir–squeeze casting method. The research focuses on the effect of casting pressure variation on the impact strength and fractographic characteristics of pure aluminum and its composites. Furthermore, it examines changes in density and microstructure due to the addition of PKSA and SiC under different casting pressures. Three main parameters were varied, namely casting pressures of 10.41, 20.82, and 31.24 MPa. The stirring process during casting was conducted for 10 minutes while maintaining a constant motor speed of 400 rpm and a furnace temperature of 750°C. Magnesium was added during casting as a wettability agent to enhance the interfacial bonding between the reinforcement particles and the aluminum matrix. The results showed that the use of PKSA as a hybrid reinforcement alongside SiC effectively improved the mechanical performance of AMC, particularly in enhancing its impact toughness. This not only strengthens the material’s structure but also supports the utilization of biomass waste into high-value engineering products. In addition, increasing the casting pressure in the stir–squeeze casting process with a composition of 95% Aluminum, 2% SiC, 2% PKSA, and 1% Magnesium significantly affected the mechanical behavior and microstructural characteristics of the composite. The variation in pressure contributed to producing a more homogeneous particle distribution and higher material density, resulting in a more optimal quality of AMC. Based on impact testing, the AMC exhibited increased material toughness with higher casting pressure. The average absorbed impact energy rose from 8.3848 J/mm² at 10.41 MPa to 9.3549 J/mm² at 20.82 MPa, reaching 9.5711 J/mm² at 31.24 MPa. The most significant improvement occurred between 10.41 and 20.82 MPa, while the difference between 20.82 and 31.24 MPa was relatively small, indicating that the relationship between pressure and toughness is not linear. Microstructural observations revealed that casting at 31.24 MPa produced the highest density (2.69 g/cm³) with nearly zero porosity (0.1%), resembling the characteristics of pure aluminum. However, the significant grain growth (68–51 μm and 64–61 μm) made the material more brittle, dominated by brittle fracture modes. In contrast, casting at 20.82 MPa resulted in more uniform grain sizes (73–46 μm and 48–43 μm) and more even particle distribution, providing an optimal balance of ductility and toughness. Meanwhile, X-Ray Diffraction (XRD) analysis revealed the presence of major phases such as Al, SiC, SiO₂ (from PKSA), and Mg in all tested samples. The strong interaction between these phases plays a crucial role in enhancing the mechanical properties of the composite. Furthermore, variations in peak intensity at different pressures indicate differences in homogeneity and particle distribution, with the most stable and balanced condition achieved at a casting pressure of 20.82 MPa.

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Detail Information

Series Title

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Call Number

T1857942025

Publisher

Indralaya : Prodi Teknik Mesin, Fakultas Teknik Universitas Sriwijaya., 2025

Collation

xvii, 98 hlm.; ilus.; tab.; 29 cm.

Language

Indonesia

ISBN/ISSN

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Classification

628.407

Content Type

Text

Media Type

unmediated

Carrier Type

other (computer)

Edition

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Subject(s)

Prodi Teknik Mesin
Limbah Cangkang Kelapa Sawit

Specific Detail Info

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Statement of Responsibility

MI

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