REVIEW PENGARUH PERLAKUAN PANAS TERHADAP PERUBAHAN STRUKTUR MIKRO, KEKUATAN DAN KEKERASAN PADUAN Al-Si-Cu-Mg

Rafdi, Muhammad Abi (2020) REVIEW PENGARUH PERLAKUAN PANAS TERHADAP PERUBAHAN STRUKTUR MIKRO, KEKUATAN DAN KEKERASAN PADUAN Al-Si-Cu-Mg. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Paduan cast Al-Si-Cu-Mg adalah paduan yang dapat diberikan perlakuan panas untuk meningkatkan sifat mekanik paduan dengan cara memunculkan presipitat. Presipitat menjadi penghalang dislokasi sehingga terjadi mekanisme precipitation hardening. Perlakuan panas yang dilakukan adalah solution heat treatment (SHT) yang diakhiri quenching, dan dilanjutkan dengan aging. Setiap tahapan perlakuan panas memberikan pengaruh pada struktur mikro. Dimulai pada tahap as-cast paduan Al-Si-Cu-Mg dapat memiliki fasa yang beragam, tergantung pada komposisi paduan. Morfologi Si eutektik dan ukuran butir juga menentukan proses precipitation hardening. Tahap SHT bertujuan untuk melarutkan Mg dan Cu, homogenisasi dan spheroidized Si. Tidak semua fasa intermetalik dapat larut, sehingga dapat memberikan efek negatif terhadap proses presipitasi. Proses quenching sangat penting untuk menjaga super saturated solid solution pada temperatur ruang, sehingga pada tahap aging presipitasi berjalan optimal. Perpaduan presipitat yang terbentuk memberikan efek penguatan baik saat koheren maupun semi-koheren dengan matriks Al. Kekuatan dan kekerasan tertinggi didapat pada kondisi peak-aged. Dengan mengamati perubahan sifat mekanik selama proses perlakuan panas dapat disimpulkan paduan Al-Si-Cu-Mg dengan presipitat θ’-Al2Cu dan Q’-Al4Cu2Mg8Si7 memberikan pengaruh pericipitation hardening terbesar (dapat meningkatkan YS ~240 MPa) diikuti paduan Al-Si-Mg dengan presipitat β”-Mg2Si dan paduan Al-Si-Cu dengan presipitat θ’-Al2Cu yang memberikan pengaruh lebih rendah. =========================================================== Cast Al-Si-Cu-Mg alloys are heat-treatable alloys. Heat treatment can cause precipitation. Precipitate hinder dislocation motion, so strengthening mechanism call precipitation hardening occurred. Solution heat treatment (SHT) with quenching, and aging are steps of heat treatment for these alloys. Each level of heat treatment affects the alloy microstructure. As-cast condition for Al-Si-Cu-Mg alloys have various phase combinations that can be occurred, depend on the alloy composition. Precipitation is also affected by the morphology of eutectic Si and microstructure dendrite size. SHT have purpose to dissolve phase containing Cu and Mg, homogenize, and spheroidize the eutectic Si. Not all intermetallic phases can dissolve, undissolved phases may alter negative effect for the precipitation. On the quenching process it’s crucial to retained the super saturated solid solution at room temperature. So, on the aging process precipitation can be optimized. Combination of all coherent and semi-coherent precipitate will make strengthening mechanism worked. Maximum strength and hardness can be obtained on peak-aged condition. Al-Si-Cu-Mg alloy with θ’-Al2Cu and Q’-Al4Cu2Mg8Si7 provide best precipitation hardening effect (by increasing YS ~240 MPa) followed by Al-Si-Mg alloy with β”-Mg2Si precipitate and Al-Si-Cu alloy with θ’-Al2Cu precipitate.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: Paduan Al-Si-Cu-Mg, Perlakuan Panas, Precipitation hardening. Al-Si-Cu-Mg alloy, Heat treatment, Precipitation hardening.
Subjects: T Technology > TN Mining engineering. Metallurgy > TN775 Aluminum alloys--Metallurgy.
T Technology > TS Manufactures > TS233 Sand casting. Metal castings--Thermal properties.
Divisions: Faculty of Industrial Technology and Systems Engineering (INDSYS) > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis
Depositing User: Muhammad Abi Rafdi
Date Deposited: 12 Aug 2020 06:29
Last Modified: 12 Aug 2020 06:29
URI: https://repository.its.ac.id/id/eprint/77695

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