Santoso, Budi and Prof. Dr. Ir. Wahyono Suprapto, MT. Met, and Dr. Eng. Yudy surya Irawan, ST., M.Eng, (2024) Pengaruh Fraksi Massa Andesit Pada Aluminum-Zinc Matrix Composite Terhadap Struktur Mikro, Porositas, Kekerasan Dan Keausan. Magister thesis, Universitas Brawijaya.
Abstract
Aluminum Matrix Composite adalah material komposit yang menggunakan Alumunium sebagai matrik dan partikel penguat seperti Andesit untuk meningkatkan sifat mekanik material. Aluminum Matrix Composite merupakan pilihan yang menarik dalam industri otomotif karena kombinasi sifat mekaniknya yang unggul, termasuk kekuatan, keuletan, dan ketahanan terhadap keausan. Partikel penguat seperti Andesit dapat menghalangi pergerakan dislokasi dalam matrik Alumunium, yang meningkatkan kekerasan dan kekuatan material melalui mekanisme penguatan partikel. Selain itu, perbedaan koefisien muai termal antara partikel penguat dan matrik Alumunium menciptakan tegangan termal yang meningkatkan densitas dislokasi di sekitar partikel penguat, yang lebih lanjut meningkatkan kekuatan material melalui penguatan dislokasi. Adanya partikel penguat juga menghambat pertumbuhan butir dalam matrik, menghasilkan ukuran butir yang lebih kecil yang meningkatkan kekuatan material melalui mekanisme penguatan ukuran butir. Metode atau proses pembuatan Aluminum Matrix Composite dalam penelitian ini menggunakan teknik metalurgi serbuk yang melibatkan pencampuran serbuk Aluminium, Zinc, dan Andesit, pengepresan dengan tekanan 400 bar, dan pemanasan pada suhu 450°C dengan variasi fraksi massa Andesit 2,5%, 5%, 7,5%, dan 10%. Pencampuran dilakukan secara manual untuk memastikan homogenitas campuran, sementara proses kompaksi dan pemanasan dilakukan dengan kontrol suhu dan tekanan yang ketat untuk mencapai sifat material yang diinginkan. Penambahan Zn dalam matriks Alumunium tidak hanya berfungsi sebagai unsur penguat tetapi juga berperan dalam pembentukan intermetallic compounds seperti MgZn2 yang meningkatkan kekerasan dan ketahanan material terhadap deformasi. Interaksi kimia antara Aluminium, Zinc, dan partikel Andesit menghasilkan struktur mikro yang lebih kuat, dan partikel Andesit yang mengandung SiO2 memberikan kontribusi tambahan terhadap kekuatan dan ketahanan aus material melalui pembentukan ikatan yang kuat dengan matrik Aluminium. Pengujian Struktur mikro dilakukan menggunakan mikroskop elektron untuk mengamati distribusi partikel penguat campuran, sementara pengujian porositas dilakukan dengan metode pengukuran densitas, di mana sampel ditimbang di udara dan dalam air untuk menentukan volume pori. Kekerasan material diuji menggunakan uji kekerasan Rockwell (HRB), dengan berbagai pengujian dilakukan pada setiap variasi fraksi massa andesit untuk mendapatkan nilai rata-rata kekerasan, dan pengujian keausan dilakukan dengan mesin uji keausan, di mana sampel digosokkan pada ring dengan beban tertentu dan keausan diukur berdasarkan berat yang hilang setelah pengujian. Hasil pengujian dan pembahasan menunjukkan bahwa partikel Andesit terdistribusi secara merata dalam matriks Al-Zn pada semua variasi fraksi massa yang diuji, yang sangat penting untuk memastikan penguatan yang efektif dalam material komposit. Pada variasi fraksi massa Andesit 10%, partikel Andesit terdistribusi lebih merata, mengurangi kemungkinan terjadinya aglomerasi yang dapat menyebabkan titik lemah dalam material. Pengujian porositas menunjukkan bahwa variasi fraksi massa andesit 5% memiliki tingkat porositas tertinggi, menunjukkan distribusi partikel yang kurang merata dan adanya kecenderungan partikel andesit untuk berkumpul. Namun, pada variasi fraksi massa andesit 10%, meskipun terjadi peningkatan porositas, kekerasan material tetap meningkat secara signifikan. Uji keausan menunjukkan bahwa penambahan fraksi massa andesit pada Aluminum Matrix Composite secara signifikan mengurangi laju keausan material, dengan variasi fraksi massa andesit 2.5% dan 7.5% menunjukkan laju keausan yang paling rendah. Hubungan antara hasil pengujian struktur mikro, porositas, kekerasan, dan keausan menunjukkan bahwa distribusi partikel yang merata dan peningkatan kekerasan material secara keseluruhan berkontribusi pada peningkatan ketahanan terhadap keausan. Dengan demikian, peningkatan fraksi massa Andesit dalam Aluminum Matrix Composite menghasilkan material yang lebih kuat, lebih keras, dan lebih tahan terhadap keausan, meskipun dengan sedikit peningkatan porositas. Penelitian ini memberikan kontribusi signifikan terhadap pemahaman tentang pengaruh fraksi massa andesit dalam Aluminum Matrix Composite, serta potensi aplikasinya dalam meningkatkan performa dan efisiensi material untuk berbagai industri.
English Abstract
Aluminum Matrix Composite is a composite material that uses Aluminum as the matrix and reinforcing particles such as Andesite to improve the mechanical properties of the material. Aluminum Matrix Composite is an attractive option in the automotive industry due to its combination of superior mechanical properties, including strength, ductility, and resistance to wear. Reinforcing particles such as Andesite can block the movement of dislocations in the Aluminum matrix, which increases the hardness and strength of the material through the mechanism of particle reinforcement. In addition, the difference in thermal expansion coefficient between the reinforcing particles and the Aluminum matrix creates thermal stress that increases the dislocation density around the reinforcing particles, which further increases the strength of the material through dislocation strengthening. The presence of reinforcement particles also inhibits grain growth in the matrix, resulting in a smaller grain size that increases the strength of the material through a grain size reinforcement mechanism. The method or process of making Aluminum Matrix Composite in this study uses powder metallurgy techniques that involve mixing Aluminum, Zinc, and Andesite powders, pressing with 400 bar pressure, and heating at 450°C with variations in Andesite mass fraction of 2.5%, 5%, 7.5%, and 10%. Mixing was done manually to ensure homogeneity of the mixture, while the compacting and heating processes were carried out with strict temperature and pressure control to achieve the desired material properties. The addition of Zn in the Aluminum matrix not only serves as a reinforcing element but also plays a role in the formation of intermetallic compounds such as MgZn2 which increases the hardness and resistance of the material to deformation. The chemical interaction between Aluminum, Zinc, and Andesite particles results in a stronger microstructure, and Andesite particles containing SiO2 make an additional contribution to the strength and wear resistance of the material through the formation of a strong bond with the Aluminum matrix. Microstructure testing was performed using an electron microscope to observe the distribution of the mixed reinforcement particles, while porosity testing was performed using the density measurement method, where samples were weighed in air and in water to determine the pore volume. The hardness of the material was tested using the Rockwell hardness test (HRB), with various tests performed on each andesite mass fraction variation to obtain an average hardness value, and The Aluminum Matrix Composite manufacturing method uses the powder metallurgy method with several important steps to produce a material with optimal mechanical properties. Aluminum powder, Zn powder and Andesite powder are mechanically mixed to ensure distribution, then compressed with 400 bar pressure to produce the material shape. After that, the mixture is heated in a mold at 450°C for 15 minutes, heating is used to strengthen particle bonds at the atomic level without melting the Aluminum. The final stage was mold disassembly and testing to determine the distribution of the Andesite particles and the strength of the material. This study shows that the Andesite particles are evenly distributed in the Al-Zn matrix without clumping, which ensures balanced reinforcement and reduces weak points in the material that can be seen in the microstructure. Increasing the mass fraction of Andesite leads to a decrease in the density of the composite, which goes hand in hand with an increase in porosity. However, the increase in porosity also increased the hardness of the material and reduced the wear rate. The highest hardness was found in the Al-Zn-7.5% Andesite variation with a value of 96 HRB. The variation in mass fraction of Andesite significantly affected the hardness of AMC compared to the base material without the addition of mass fraction of Andesite, indicating that Andesite functioned effectively as a reinforcement. The lowest wear rate was found in the Al-Zn-2.5% and Al-Zn-7.5% Andesite variations at 0.03 mg/s, while Al-Zn-5% Andesite experienced a significant increase in wear rate at 0.16 mg/s. Overall, the addition of Andesite into AMC improved the mechanical properties of the material, especially in terms of hardness and resistance to wear. The test results and discussion show that the Andesite particles are evenly distributed in the Al-Zn matrix at all tested mass fraction variations, which is very important to ensure effective reinforcement in composite materials. In the 10% Andesite mass fraction variation, the Andesite particles were more evenly distributed, reducing the possibility of agglomeration which can cause weak points in the material. Porosity testing showed that the 5% andesite mass fraction variation had the highest porosity level, indicating a less even distribution of particles and a tendency for andesite particles to aggregate. However, in the 10% andesite mass fraction variation, despite the increase in porosity, the hardness of the material still increased significantly. Wear tests showed that the addition of andesite mass fraction to the Aluminum Matrix Composite significantly reduced the wear rate of the material, with the 2.5% and 7.5% andesite mass fraction variations showing the lowest wear rate. The relationship between the microstructure, porosity, hardness, and wear test results showed that the even distribution of particles and the overall increase in hardness of the material contributed to the improved resistance to wear. Thus, increasing the mass fraction of Andesite in the Aluminum Matrix Composite resulted in a stronger, harder, and more wear-resistant material, albeit with a slight increase in porosity. This research has resulted in.
| Item Type: | Thesis (Magister) |
|---|---|
| Identification Number: | 0424070207 |
| Uncontrolled Keywords: | AMC, Al-Zn, Andesit, Struktur Mikro, Porositas, Kekerasan, Keausan. |
| Divisions: | S2/S3 > Magister Teknik Mesin, Fakultas Teknik |
| Depositing User: | S Sucipto |
| Date Deposited: | 26 Aug 2024 04:39 |
| Last Modified: | 26 Aug 2024 04:39 |
| URI: | http://repository.ub.ac.id/id/eprint/229259 |
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