Mekanik Alaşımla Süresince Al85Co7Y8 Alaşımının Faz Değişimi

Öz

Bu çalışmada nanoyapılı Al₈₅Co₇Y₈ (at.%) alaşımı, mekanik alaşımlama (MA) tekniği kullanılarak elemental tozların katı hal reaksiyonuyla sentezlenmiştir. Toz alaşımlar, argon gazı altında sertleştirilmiş paslanmaz çelik hazne ve bilyeler kullanılarak yüksek-enerjili bilyeli değirmen içerisinde 300 saatlik öğütme işlemine tabi tutulmuştur. Öğütme işlemi süresince numunelerdeki yapısal ve morfolojik değişimler X-ışını difraksiyonu (XRD) ve taramalı elektron mikroskobu (SEM) ile termal kararlılıkları ise diferansiyel termal analiz (DTA) ile incelenmiştir. MA işlemi sonucunda aşırı doymuş fcc-Al katı çözelti fazı içeren alaşımlar üretilmiştir. Al₈₅Co₇Y₈ alaşımının 300 saatlik öğütme işlemi sonrasındaki kristalit boyutu yaklaşık 16 nm olarak bulunmuştur.

Anahtar Kelimeler

• Al-Co-Y alaşımı,Nanokristal alaşım,Mekanik alaşımlama,Faz değişimi

Phase Evolution of Al85Co7Y8 Alloy during Mechanical Alloying

Öz

In this study, the nanostructured Al₈₅Co₇Y₈ (at.%) alloy was synthesized by a solid state reaction from the constituent elemental powder mixture via mechanical alloying (MA). The powder mixture was ball milled for times up to 300 h in a planetary high energy mill using hardened steel media under argon atmosphere. Structural and morphological changes during the milling process were characterized by a combination of X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Thermal stability of the milled powders was investigated using differential thermal analysis (DTA). The results showed that supersaturated α-Al solid solution was formed in the whole content of the milled material. The mechanically alloyed Al₈₅Co₇Y₈ powder for 300 h of milling indicated the formation of fine nanoparticles with a size of about 16 nm.

Anahtar Kelimeler

• Al-Co-Y alloy,Nanocrystalline alloy,Mechanical alloying,Phase evolution

Kaynakça

1. [1] Suryanarayana, C. (2004). Mechanical alloying and milling. Marcel Dekker, New York, USA. 466s.
2. [2] Inoue, A. (1998). Amorphous, nanoquasicrystalline and nanocrystalline alloys in Al-based systems. Prog. Mater. Sci., 43, 365-520.
3. [3] Viet, N.H., Oanh, N.T.H., Quynh, P.N.D., Lap, T.Q. ve Kim, J.S. (2015). Thermal stability of amorphous Al-Fe-Y prepared by mechanical alloying. Mater. Sci. Forum, 804, 271-274.
4. [4] Inoue, A. (2000). Stabilization of metallic supercooled liquid and bulk amorphous alloys, Acta Mater., 48, 279-306.
5. [5] Gogebakan, M. (2004). Thermal stability and mechanical properties of Al-based amorphous alloys. J. Mater. Proc Techn., 153-154, 829-832.
6. [6] Avar, B., Gogebakan, M., Tarakci, M., Gencer, Y. ve Kerli, S. (2013). Microstructural investigations of rapidly solidified Al-Co-Y alloys. Adv. Mater. Sci. Eng., Article ID 163537.
7. [7] Sun, Z., Xing, Q., Axinte, E., Ge, W., Leng, J. ve Wang, Y. (2015). Formation of highly thermal stable Al88Ni6Y6 amorphous composite by graphene addition design. Mater. Design, 81, 59-64.
8. [8] Wang, T., Sun, Z., Zhang, L. ve Wang, Y. (2016). Glass formation and thermal stability of mechanically alloyed Al75Ni10Ti10Zr5 amorphous composites with graphene addition. Mater. Sci. Forum, 849, 58-63.

9. [9] Maurya, R.S., Sahu, A. ve Laha, T. (2016). Effect of consolidation pressure on phase evolution during sintering of mechanically alloyed Al86Ni8Y6 amorphous powders via spark plasma sintering. Mater. Sci. Eng. A, 649, 48-56.
10. [10] Börner, I. ve Eckert, J. (2001). Phase formation and properties of mechanically alloyed amorphous Al85Y8Ni5Co2. Scripta Mater., 45, 237-244.
11. [11] Calin, M., Grahl, H., Adam, M., Eckert, J. ve Schultz, L. (2004). Synthesis and thermal stability of ball-milled and melt-quenched amorphous and nanostructured Al-Ni-Nd-Co alloys. J. Mater. Sci., 39, 5295-5298.
12. [12] Zhang, L.C., Calin, M., Branzei, M., Schultz, L. ve Eckert, J. (2007). Phase stability and consolidation of glassy/nanostructured Al85Ni9Nd4Co2 alloys. J. Mater. Res., 22, 1145-1155.
13. [13] Prashanth, K.G., Scudino, S., Murty, B.S. ve Eckert, J. (2009). Crystallization kinetics and consolidation of mechanically alloyed Al70Y16Ni10Co4 glassy powders. J. Alloys Comp., 477, 171-177.
14. [14] Viet, N.H., Oanh, N.T.H., Quynh, P.N.D., Lab, T.Q. ve Kim, J.S. (2015). Thermal stability of amorphous Al-Fe-Y prepared by mechanical alloying. Mater. Sci. Forum, 804, 271-274.
15. [15] Manna, I., Chattopadhyay, P.P., Banhart, F. ve Fecht, H.J. (2004). Development of amorphous and nanocrystalline Al65Cu35-xZrx alloys by mechanical alloying. Mater. Sci. Eng. A, 379, 360-365.
16. [16] Samanta, A., Manna, I. ve Chattopadhyay, P.P. (2007). Phase evolution in Al-Ni-(Ti, Nb, Zr) powder blends by mechanical alloying. Mater. Sci. Eng. A, 464, 306-314.
17. [17] Chen, H., Cheng, X., Zhang, J., Ouyang, Y., Du, Y., Zhong, X. ve Tao, X. (2008). The compositional range of amorphous phase formation and thermal stability of Al90-xFe5Ni5Cex. J. Alloys Comp., 460, 309-313.
18. [18] Mula, S., Ghosh, S. ve Pabi, S.K. (2009). On the formation of phases by mechanical alloying and their thermal stability in Al-Mn-Ce system. Powder Tech., 191, 176-181.
19. [19] Cullity, B.D., Stock, S.R. (2001). Elements of X-ray diffraction. 3 rd. Edition, Prentice Hall, New-Jersey, USA. 664s.
20. [20] Suryanarayana, C. (2001). Mechanical alloying and milling. Prog. Mater. Sci., 46: 1-184.
21. [21] Nayak, S.S., Wollgarten, M., Banhart, J., Pabi, S.K. ve Murty, B.S. (2010). Nanocomposites and an extremely hard nanocrystalline intermetallic of Al-Fe alloys prepared by mechanical alloying. Mater. Sci. Eng. A Mater. Sci. Eng. A, 527, 2370-2378.
22. [22] Nayak, S.S., Pabi, S.K. ve Murty, B.S. (2010). Al-(L12)Al3Ti nanocomposites prepared by mechanical alloying: synthesis and mechanical properties. J. Alloys Comp., 492, 128-133.