微量元素对Cu-Zr-Al块体金属玻璃形成能力及力学性能的影响

Effects of minor alloying additions on glass forming ability and mechanical properties of Cu-Zr-Al bulk metallic glasses

研究微量元素Ag、Ti、Ga、Ni和Sn对Cu55Zr38Al7铜基块体金属玻璃形成能力及力学性能的影响。结果表明:添加2%(摩尔分数)的Ag、Ti或Ga均可以提高Cu55Zr38Al7合金的玻璃形成能力;用6%的Ag替代Cu,玻璃棒的临界直径可从2 mm增加到4 mm;因此,替代化学性质相似的元素或者扩大合金系的原子尺寸范围对提高玻璃形成能力具有显著的效果;然而,添加微量元素均不同程度地降低Cu-Zr-Al金属玻璃的硬度。断口表面形貌显示;微量相似元素替代影响基体在压缩过程中剪切带的繁殖;在微量元素替代的伪四元铜基块体金属玻璃中,2%Ti和2%Ag替代可分别获得最大压缩强度2 163 MPa和最大压缩应变8.7%。因此,通过添加微量元素可以调谐金属玻璃的玻璃形成能力和力学性能。

The effects of minor additions of Ag,Ti,Ga,Ni and Sn on the glass forming ability（GFA） and mechanical properties of Cu55Zr38Al7 bulk metallic glass were investigated.The results show that the GFA of Cu55Zr38Al7 bulk metallic glass is enhanced by 2%（mole fraction） addition of Ag,Ti or Ga.The critical size of the cast metallic glass rod is enlarged from 2 to 4 mm by 6%Ag addition.Obviously,distinct effects on GFA are obtained by the substitution of chemically similar elements or the enlargement of atom dimension extension in the alloying system.However,Vickers hardness of Cu-Zr-Al BMG decreases with each element substitution.The fracture surface demonstrates the minor similar elements substitution contribution to the propagation behaviour of shear bands during the compressive deformation process.The highest compressive fracture strength of 2 163 MPa and the highest compressive strain of 8.7% are obtained in the pseudo-quaternary Cu-based BMGs with 2%Ti and 2%Ag substitution,respectively.Consequently,GFA and mechanical properties of the bulk metallic glasses can be coordinated by minor alloying additions.