Sains Malaysiana 42(12)(2013): 1751–1754

Fabrication of in-situ Fe-NbC Composite by Mechanical Alloying

(Fabrikasi Komposit F-NbC in-situ Secara Pengaloian Mekanikal)

SITI ZALIFAH MD RASIB & HUSSAIN ZUHAILAWATI*

School of Materials and Mineral Resources Engineering, Engineering Campus,

Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia

Diserahkan: 21 Mac 2012/Diterima: 28 Mei 2012

ABSTRACT

In this research we investigated the in-situ formation mechanism of NbC in mechanically alloyed Fe-Nb-C mixture. Powders of iron, niobium and graphite with a composition Fe-20 %Nb was milled in a planetary mill for various milling times (i.e. 5, 10, 15 and 20 h) to investigate the influence of this variable on phase formation and properties of composite. The mixture was cold pressed and sintered at 1300°C for 1 h. Only phase of the initial raw materials was observed after milling, whilst NbC phase was detected after sintering. Increasing the milling time resulted in an increase in crystallite size and strain energy, which is beneficial for hardness and density improvement.

Keywords: Fe matrix; mechanical alloying; milling speed; NbC phase; powder metallurgy

ABSTRAK

Dalam penyelidikan ini, kami menerangkan mekanisme pembentukan NbC secarain situ di dalam campuran Fe-Nb-C yang dialoi secara mekanikal. Serbuk besi, niobium dan grafit dengan komposisi Fe-20 % NbC (pecahan isi padu) dikisar di dalam pengisar planet untuk pelbagai tempoh (5, 10, 15 dan 20 jam) bagi menjelaskan pengaruh pemboleh ubah tersebut terhadap pembentukan fasa dan sifat komposit. Campuran ditekan sejuk dan disinter pada 1300°C selama 1 jam. Hanya bahan mentah awal sahaja yang diperhatikan selepas pengisaran manakala fasa NbC dikenal pasti terbentuk selepas pensinteran. Penambahan tempoh pengisaran menghasilkan pertambahan dalam saiz hablur dan tenaga terikan yang memberikan kekuatan dan memperbaiki ketumpatan.

Kata kunci: Fasa NbC; halaju pengisaran; matriks Fe; metalurgi serbuk; pengaloian mekanikal

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*Pengarang untuk surat-menyurat, email: zuhaila@eng.usm.my