Hydrogen Internal Friction Peak in Amorphous Zr-Cu-Al-Si Alloys

抄録

The hydrogen internal friction peak (HIFP) in amorphous (a-) Zr₆₀Cu_40−yAl_y (y=0,10), a-Zr₅₀Cu₅₀, a-Zr₄₀Cu₆₀ and a-Zr₄₀Cu_50−xAl₁₀Si_x (x=0,1,3) are studied to pursue a high-strength and high-damping performance as well as the underlying process for the HIFP in a-alloys. The tensile strength, σ_f, of a-Zr₆₀Cu₃₀Al₁₀, a-Zr₄₀Cu₅₀Al₁₀ and a-Zr₄₀Cu₄₉Al₁₀Si₁ increases from about 1.5 GPa to 2 GPa with increasing hydrogen concentration, C_H, to 20 at%. One part of a-Zr₆₀Cu₃₀Al₁₀, a-Zr₄₀Cu₅₀Al₁₀ and a-Zr₄₀Cu₄₉Al₁₀Si₁ specimens show a very high HIFP beyond 3×10⁻² in the as hydrogen charged state, where the hydrogen induced structural relaxation (HISR) proceeds above room temperature. A maximum value of the HIFP, Q_p⁻¹, after the HISR shows a moderate increase with increasing C_H, about 1×10⁻² at C_H of 10 at%. The combination of σ_f and Q_p⁻¹ data indicates that a-Zr₆₀Cu₄₀Al₁₀(H), a-Zr₄₀Cu₅₀Al₁₀(H) and a-Zr₄₀Cu₄₉Al₁₀Si₁(H) after the HISR are potential materials with a high-strength and high-damping performance. The peak temperature of the HIFP, T_p, at 10 at%H is 309 K, 270 K and 220 K with the measurement frequency of about 200 Hz for a-Zr₄₀Cu₄₉Al₁₀Si₁, a-Zr₄₀Cu₅₀Al₁₀ and a-Zr₆₀Cu₃₀Al₁₀, respectively. It is noted that T_p found for a-Zr₄₀Cu₄₉Al₁₀Si₁ shows a breakthrough for an elevation of T_p of the HIFP in a-alloys, and that a composite material composed of these a-alloys can serve a high-damping performance in a wide temperature range or a wide frequency range. For the underlying process of the HIFP, the Q_p⁻¹ vs. C_H data shows a camel’s humps like change for a-Zr₅₀Cu₅₀ and a-Zr₄₀Cu₆₀, suggesting that only one part of hydrogen atoms can contribute to the HIFP . In contrast, Q_p⁻¹ shows a monotonous increase with increasing C_H for C_H below 20 at% for a-Zr₆₀Cu_40−yAl_y (y=0,10) and a-Zr₄₀Cu_50−xAl₁₀Si_x (x=0,1,3), suggesting that most of hydrogen atoms are associated with the HIFP in the a-alloys. For the relaxation parameters of the HIFP, values of 1/τ₀ fall in the range expected for a simple relaxation process for a-Zr₆₀Cu_40−yAl_y (y=0,10) and a-Zr₄₀Cu_50−xAl₁₀Si_x (x=0,1,3), but are extremely high for a-Zr₅₀Cu₅₀ and a-Zr₄₀Cu₆₀, where τ₀ denotes the pre-exponential factor of the relaxation time. These results are discussed in the light of the amorphous structures in the a-alloys.