Sains Malaysiana 47(4)(2018): 811-817

http://dx.doi.org/10.17576/jsm-2018-4704-21 

Alloying Behavior and Microstructural Changes of a Ti-10%Mo-10%Cr Alloy on Sintering Process

(Sifat Pengaloian dan Perubahan Mikrostruktur Aloi Ti-10%Mo-10%Cr ke atas Proses Sinter)

JUNAIDI SYARIF¹*, EKO KURNIAWAN², TUBAGUS N. ROHMANNUDIN², MOHAMAD RASIDI RASANI² & ZAINUDDIN SAJURI²

¹University of Sharjah, College of Engineering, Sharjah, UAE

²Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

Diserahkan: 17 Oktober 2016/Diterima: 25 Oktober 2017

ABSTRACT

This study aimed to investigate the effects of element diffusion on the alloying behaviour and microstructure of a Ti-10%Mo- 10%Cr alloy during sintering and furnace cooling. A theoretical calculation of the average diffusion distance for each element was performed to predict the alloying behaviour during sintering and furnace cooling. The Ti-10%Mo-10%Cr alloy was fabricated using a blended element powder metallurgy approach. Micrograph of the samples after sintering showed bright-circle structures and significantly decreased equiaxed structures. The number of plate-like structures increased with prolonged sintering time. Microstructural changes occurred because of element diffusion resulting from the prolonged sintering time. Moreover, the diffusion distance of each element also increased with prolonged sintering time. Although elements can sufficiently diffuse during both sintering and furnace cooling, the diffusion distance during sintering was considerably higher than that during furnace cooling for all elements. The diffusion distances of Cr and Mo were the highest and lowest, respectively, during sintering and furnace cooling. This study showed that alloying behaviour mostly occurred during sintering and was controlled by the diffusion of Mo atoms.

Keywords: Diffusion; microstructure; powder metallurgy; sintering; Ti alloy

ABSTRAK

Kajian ini bertujuan untuk mengkaji kesan peresapan unsur terhadap kelakuan pengaloian dan mikrostruktur pada aloi Ti-10%Mo-10%Cr semasa sinteran dan penyejukan relau. Pengiraan secara teori terhadap jarak peresapan purata bagi setiap unsur dilakukan untuk meramal kelakuan pengaloian semasa sinteran dan penyejukan relau. Aloi Ti-10%Mo- 10%Cr telah direka menggunakan pendekatan metalurgi serbuk unsur sebati. Mikrograf sampel selepas pensinteran menunjukkan struktur bulatan-terang dan struktur sama paksi yang menurun secara ketara. Bilangan struktur seperti plat meningkat dengan memanjangkan masa pensinteran. Perubahan mikrostruktur berlaku disebabkan penyebaran unsur yang dihasilkan semasa pensinteran yang berpanjangan. Selain itu, jarak resapan bagi setiap elemen juga meningkat dengan masa pensinteran berpanjangan. Walaupun unsur-unsur boleh cukup meresap semasa sinteran dan penyejukan relau, jarak resapan semasa sinteran adalah lebih tinggi daripada semasa penyejukan relau untuk semua unsur. Jarak peresapan Cr dan Mo masing-masing yang tertinggi dan terendah, semasa sinteran dan penyejukan relau. Kajian ini menunjukkan bahawa kelakuan pengaloian kebanyakannya berlaku semasa sinteran dan dikawal oleh resapan atom Mo.

Kata kunci: Aloi Ti; metalurgi serbuk; mikrostuktur; pensinteran; peresapan

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*Pengarang untuk surat-menyurat; email: sjunaidi@sharjah.ac.ae