Zr-Cu-Ni-Al-Nb大块非晶合金的晶化行为、力学性能及电化学腐蚀行为的研究

利用水冷铜模铸造法成功制备了Zr_65-xCu_17.5Al_7.5Ni ₁₀Nb_x (x=0，2，5)大块非晶合金. X射线衍射、热分析研究结果表 明，Nb的添加显著改变了非晶合金的晶化行为，促进了二十面体准晶相的形成. 各合金的准 静态压缩实验表明，Nb的适量添加有利于提高大块非晶合金的强度和塑性. 其中x=5的大块 非晶合金的抗压强度σ_b和塑性应变量ε_p 关键词： Zr基大块非晶合金 晶化行为 力学性能 耐腐蚀性能

Crystallization, mechanical and corrosion properties of Zr-Cu-Ni-Al-Nb bulk glassy alloys

Zr_65-xCu_17.5Al_7.5Ni₁₀Nb_x bulk metallic glasses (BMGs) with x=0, 2 and 5 were prepared by water-cooled cop per mold casting. X-ray diffraction and differential scanning calorimetry reveal ed that the addition of Nb changes crystallization pathway of the base alloy and promotes an initial formation of icosahedral quasicrystals. The mechanical prop erties of the BMGs prepared were measured with MTS in a mode of quasi-static com pression. It was found that the addition of an appropriate amount of Nb signific antly enhances the compression strength and plastic strain with the maximum valu e of σ_b =1741MPa and ε_p= 5.0% for the BMG containing 5at % Nb. In addition, the corrosion behavior of the BMGs was investigated in 3% NaC l aqueous solution by electrochemical measurements. It showed that the BMGs with different compositions are all spontaneously passivated with passive current de nsity of 10^-6—10^-5 A/cm², which is three order of magnitude lower than that of 1Cr18Ni9Ti stainless steel. The corrosion resis tance of the BMGs can be further enhanced with the addition of Nb, as indicated by the increase in pitting potential with the increase of Nb content.