Effect of Aging Temperature on Microstructure and Hardness of CoCrFeNiTi_0.5 High Entropy Alloy

Abstract:

A bulk casting ingot (Ø70 × 150mm) of CoCrFeNiTi_0.5 high entropy alloy was prepared by vacuum medium frequency induction melting. The samples from the ingot were aged for 12h in the temperature range of 900-1100°C and then quenched in water to investigate the effect of aging temperature on the microstructure and hardness of CoCrFeNiTi_0.5 alloy. The crystalline structure of as-cast CoCrFeNiTi_0.5 alloy consisted of the principal face-centered cubic (FCC) dendrite phase plus (Ni, Ti)-rich R phase, (Fe, Cr)-rich σ phase, (Co, Ti)-rich Laves phase within the inter-dendrite area. The dendrite contained approximately equivalent amount of Co, Cr, Fe, Ni and a smaller amount of Ti element. After aging treatment in the temperature range of 900-1000°C, the (Co, Ti)-rich phase disappeared while the amount of (Ni, Ti)-rich phase and (Fe, Cr)-rich phase increased. But the volume fraction of FCC dendrite phase increased and the intermetallic phases decreased after aging at 1100°C. The micro-hardness and the macro-hardness of the as-cast CoCrFeNiTi_0.5 alloy were HV616.8 and HRC52, respectively. After heat treatment at 1000°C, the micro-hardness and macro-hardness decreased from HV616.8 to HV386.8 and from HRC52 to HRC42.7, respectively.

• Periodical: Materials Science Forum (Volume 789)
• Pages: 48-53
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.789.48
• Online since: April 2014
• Authors: Yong Dong*, Qiu Shi Chen, Yi Ping Lu, Peng Chao Zhang, Ting Ju Li
• Keywords: Hardness, Heat Treatment, High Entropy Alloy, Microstructure

References

[1] J.W. Yeh, S.K. Chen, S.J. Lin, J.Y. Gan, T.S. Chin, and T.T. Shun: Adv Eng Mater Vol. 6 (2004), p.299

[2] B. Cantor, I.T.H. Chang, P. Knight, and A.J.B. Vincent: Mater. Sci. Eng. A Vol. 375-377 (2004), p.213

[3] O.N. Senkov, G.B. Wilks, D.B. Miracle, C.P. Chuang, and P.K. Liaw: Intermetallics Vol. 18 (2010), p.1758

DOI: 10.1016/j.intermet.2010.05.014

[4] C.Y. Hsu, C.C. Juan, W.R. Wang, S.T. Shen, J.W. Yeh, and S.K. Chen: Mater. Sci. Eng. A Vol. 528 (2011), p.3581

[5] C.J. Tong, M.R. Chen, S.K. Chen, J.W. Yeh, T.T. Shun, and S.J. Lin: Metal. Trans. A Vol. 36 (2005), p.1263

[6] Y.Y. Du, Y.P. Lu, T.J. Li, T.M. Wang, and G.L. Zhang: Mater. Res. Innovation Vol. 15 (2011), p.107

[7] Y.Y. Du, Y.P. Lu, T.M. Wang, T.J. Li,and G.L. Zhang: Procedia Engineering Vol 27 (2012), p.1129

[8] B. Ren, Z.X. Liu, D.M. Li, L. Shi, B. Cai, and M.X. Wang: Mater. Corros Vol. 63 (2012), p.828

[9] H.B. Cui, Y. Wang, J.Y. Wang, X.F. Wang, and H.Z. Fu: Research＆Development Vol. 8 (2011), p.259

[10] Y.J. Zhou, Y. Zhang, Y.L. Wang, and G.L. Chen: Appl. Phys. Lett Vol. 90 (2007), pp.181904-1

[11] Y. Dong, Y.P. Lu, J.J. Zhang, and T.J. Li: Mater. Sci. Forum Vol. 745-746 (2012), p.775

[12] F.R. Boer, D.G. Perrifor (Eds.), Cohesion in Metals, Elsevier, Amsterdam, (1988)

[13] K.B. Zhang, and Z.Y. Fu: Intermrtallics Vol. 22 (2012), p.24

[14] F. Otto, Y. Yang, H. Bei, and E.P. George: Acta Mater Vol. 61 (2013) p.2628

[15] S. Guo, C. Ng, J. Lu, and C.T. Liu: J. Appl. Phys Vol. 109 (2011), p.103505

[16] Y. Zhang, Y.J. Zhou, J.P. Lin, G.L. Chen, and P.K. Liaw: Adv. Eng. Mater Vol. 10 (6) (2008), p.534

[17] X. Yang, and Y. Zhang: Mater. Chem. Phys Vol. 132 (2012), p.233

[18] T.T. Shun, L.Y. Chang, and M.H. Shiu: Mater. Sci. Eng. A Vol. 556 (2012), p.170