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Efendi Mabruri
Pusat Penelitian Metalurgi - LIPI

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PENGUATAN TEMBAGA MURNI DENGAN TEKNIK EQUAL CHANNEL ANGULAR PRESSING Solihin Solihin; Efendi Mabruri; I Nyoman Gede Putrayasa
Metalurgi Vol 26, No 3 (2011): Metalurgi Vol. 26 No. 3 Desember 2011
Publisher : National Research and Innovation Agency (BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (411.908 KB) | DOI: 10.14203/metalurgi.v26i3.20

Abstract

Penguatan tembaga murni dengan metode Equal Angular Channel Pressing telah dilakukan terhadap tembaga murni. Hasil pengerjaan ECAP dengan jalur ekstrusi ECAP rute Bc, dimana benda kerja diputar 90 ° setiap pass, menghasilkan pembelahan grain menjadi sub-grain yang memiliki ukuran yang menurun drastis dengan sudut butir yang lebih kecil.  Seiring dengan penurunan besar butir, kekerasan tembaga tersebut meningkat drastis. AbstractThe hardness of high purity copper has been increased through Equal Angular Channel Pressing method. The application of ECAP method with extrution rute Bc , in which the sample was rotated 90° for each pass, result in the generation of sub-grain within the grain. The size of new grain (sub –grain) is drastically smaller than initial grain and also has low angle. With the decreasing of grain size, the hardness drastically increases.
PERANAN UNSUR REFRAKTORI DIDALAM NICKEL-BASED SUPERALLOYS: SUATU REVIEW[ Efendi Mabruri
Metalurgi Vol 26, No 2 (2011): Metalurgi Vol.26 No.2 Agustus 2011
Publisher : National Research and Innovation Agency (BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (911.905 KB) | DOI: 10.14203/metalurgi.v26i2.11

Abstract

Nickel based superalloys digunakan secara luas sebagai sudu turbin gas mesin pesawat dan pembangkit listrik karena memiliki kapabilitas suhu tinggi yang dapat mempertahankan kakuatan struktur dan stabilitas permukaan. Penambahan unsur refraktori terutama rhenium (Re) ke dalam superalloy berbasis nikel berpengaruh besar terhadap peningkatan kekuatan mekanik pada suhu tinggi khususnya ketahanan terhadap creep. Akan tetapi penambahan dengan jumlah yang besar akan mengakibatkan munculnya fasa TCP yang tidak diinginkan pada kondisi operasi suhu tinggi. Tulisan ini akan mengulas “the role” dari unsur Re ini di dalam superalloy berbasis nikel  terutama dikaitkan dengan faktor-faktor penting di dalam material suhu tinggi. Faktor-faktor yang diulas adalah  koefisien partisi, misfit kisi, dan perilaku interdifusi unsur rhenium  didalam paduan nikel. Akan diulas juga pengembangan nickel based superalloys generasi keempat yang mengandung komposisi yang cocok antara Re dan Ru. AbstractNickel based superalloys are widely used in the aircraft engine and in the land-based gas turbine as the blade material due to its high temperature capability to maintain structural strength and surface stability at elevated temperatures. The addition of refractory elements, particularly rhenium into single crystal nickel based superalloys increases high temperature mechanical properties remarkably especially creep resistance. However, the addition of refractory elements in a large amount in the superalloys induces the formation of the deleterious TCP phases at high temperature. This paper overviews the role of rhenium in the single crystal nickel based superalloys in relation with the important factors in the high temperature processes such as partition coefficient, lattice misfit and interdiffusion behavior of rhenium in the superalloys. In addition, the development of the fourth generation of single crystal nickel based superalloys containing rhenium and ruthenium is discussed briefly