Grain boundary diffusion and segregation of Ni in Cu

✍ Scribed by Sergiy Divinski; Jens Ribbe; Guido Schmitz; Christian Herzig

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 255 KB
• Volume: 55
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/j.actamat.2007.01.032

✦ Synopsis

Grain boundary (GB) diffusion of 63 Ni in polycrystalline Cu was investigated by the radiotracer technique in an extended temperature interval from 476 to 1156 K. The independent measurements in Harrison's C and B kinetic regimes resulted in direct data of the GB diffusivity D gb and of the so-called triple product P = s AE d AE D gb (s and d are the segregation factor and the diffusional GB width, respectively). Arrhenius-type temperature dependencies for both the D gb and P values were measured, resulting in the pre-exponential factors D 0 gb ¼ 6:93 Â 10 À7 m 2 s À1 and P 0 = 1.89 • 10 À16 m 3 s À1 and the activation enthalpies of 90.4 and 73.8 kJ mol À1 , respectively. Although Ni is completely soluble in Cu, it reveals a distinct but still moderate ability to segregate copper GBs with a segregation enthalpy of about À17 kJ mol À1 .