Title: Effect of Co addition on deformation-induced martensitic transformation in Cu-Zr alloy

Authors: Jeong-Soo Kim; Byung-Jin Kim; Woo-Chul Kim; Min-Young Na; Do-Hyang Kim; Won-Tae Kim

Addresses: Center for Noncrystalline Materials, Department of Materials Science & Engineering, Yonsei University, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea ' Center for Noncrystalline Materials, Department of Materials Science & Engineering, Yonsei University, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea ' Center for Noncrystalline Materials, Department of Materials Science & Engineering, Yonsei University, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea ' Center for Noncrystalline Materials, Department of Materials Science & Engineering, Yonsei University, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea ' Center for Noncrystalline Materials, Department of Materials Science & Engineering, Yonsei University, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea ' Department of Optical Engineering, Cheongju University, 36 Naedok-dong, Sangdang-gu, Cheongju, Chungbuk 360-764, South Korea

Abstract: Thermal stability, phase transformation after deformation and mechanical properties of B2 phase alloy with the compositions of Cu50-xCoxZr50 (x = 2, 4, 6, 10, 15, 20, 25, 30, 40, 45 and 50) have been investigated in the present study. The addition of Co in Cu50Zr50 alloy effectively improves the stability of B2 phase. The Ms and As temperatures generally decrease with increasing Co content. Before deformation, the alloys with x = 10, 15, 20, 25, 30, 40, 45 and 50 consist of B2 phase. After deformation, B2-B19´ martensitic transition occurs in x = 10, 15, 20 and 25 alloys, and B2-B33 martensitic transition occurs in x = 50 alloys. No martensitic transformation occurs in x = 40 and 45 alloys. The alloys with x = 10, 15, 20 and 25 exhibit double yielding phenomenon and higher strain-hardening rate, owing to B2-B19´ martensitic transformation during deformation. The alloys with x = 30, 40, 45 and 50 exhibit lower strain-hardening rate, in spite of conventional dislocation slip or B2-B33 martensitic transformation.

Keywords: copper; cu-zr alloys; zirconium; B2 phase; martensitic transformation; cobalt; thermal stability; phase transformation; deformation; mechanical properties; martensitic transition; metallic glasses; double yielding; strain hardening.

DOI: 10.1504/IJNT.2016.077078

International Journal of Nanotechnology, 2016 Vol.13 No.4/5/6, pp.278 - 287

Received: 08 May 2021
Accepted: 12 May 2021

Published online: 19 Jun 2016 *

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