The impurity diffusion of Zr was determined (using Ti/Ti-3.06at%Zr couples) at 1173 to 1773K, under pressures of between 0.1MPa and 3.0GPa. It was found that the Arrhenius plots had a marked upward curvature, and that the degree of curvature increased with increasing pressure. The data could be described by the expressions:

0.1MPa:     D (m2/s) = 0.000159 exp[-316(kJ/mol)/RT] exp[136(MJK/mol)/RT2]

1.0GPa:     D (m2/s) = 0.000160 exp[-322(kJ/mol)/RT] exp[140(MJK/mol)/RT2]

2.1GPa:     D (m2/s) = 0.000162 exp[-329(kJ/mol)/RT] exp[145(MJK/mol)/RT2]

3.0GPa:     D (m2/s) = 0.000164 exp[-334(kJ/mol)/RT] exp[148(MJK/mol)/RT2]

The activation volumes which were deduced from the isothermal pressure dependence of the diffusion coefficient were between 22 and 36% of the atomic volume of the host metal.

H.Araki, Y.Minamino, T.Yamane, T.Nakatsuka, Y.Miyamoto: Metallurgical and Materials Transactions A, 1996, 27[7], 1807-14