Zr₆₀Cu₂₅Al₁₀Ni₅バルク金属ガラスの常温強度特性に及ぼす熱塑性変形条件の影響

抄録

The influence of thermoplastic deformation on the mechanical properties of Zr₆₀Cu₂₅Al₁₀Ni₅ bulk metallic glass (BMG) at room temperature was studied experimentally. The strength of this BMG at room temperature after thermoplastic deformation can be decreased with deformation under a hot condition, even if the thermal condition does not exceed the specific TTT curve of this material and does not induce crystallization with embrittlement. It is supposed that the crystallization is caused not only by thermal condition but also by plastic deformation, and induces the decrease in the strength and embrittlement. Therefore the increase in the thermoplastic strain tends to promote the crystallization, and decrease the fracture stress at room temperature. However, it is confirmed experimentally that a high strain rate and low temperature is effective to avoid the decrease in the fracture stress at room temperature although the thermoplastic strain increases.