Ti-Zr-Ni-Cu非晶系的等电子浓度特征

e/a-CONSTANT CHARACTERISTICS IN Ti-Zr-Ni-Cu GLASS-FORMING SYSTEM

以准晶成分Ti40Zr40Ni20为基准,在Ti-Zr-Ni-Cu系中设计出电子浓度为1．200和原子尺寸为0．1474 nm的系列合金,并用铜模吸铸法制备直径为3 mm的合金棒试样．结果表明, Ti12Zr55Ni13Cu20成分附近可形成块体非晶合金, 而Ti3Zr60Ni12CU25和Zr60Ni10Cu30成分点上形成了单一的四方Zr2Cu型非晶相关相．准晶、块体非晶合金和Zr2Cu相是具有相同电子浓度的电子化合物,它们在成分图上表现出鲜明的等电子浓度特征,表明块体非晶合金的等电子浓度判据适用于 Ti-Zr-Ni-Cu非晶系．二十面体与截角八面体间的结构关联可作为准晶或非晶合金多型性转变成Zr2Cu相的结构模型．

A series of alloys with e/a （i.e. valence electron per atom） value of 1.200 and Ra （average atomic size） of 0.1474 nm has been designed in Ti-Zr-Ni-Cu system based on the quasicrystalsforming composition Ti40Zr40Ni20, then the alloy rods with diameter of 3 mm were fabricated by the conventional suction casting method. The experiments showed that a bulk glass alloy can be obtained in the vicinity of Ti12ZrssNi13Cu20, and at the compositions of Ti3Zr60Ni12Cu2s and Zr60NiloCu30 the another glass-related phase tI-Zr2Cu is formed. The above quasicrystal, bulk metallic glass and tI-Zr2Cu phase are a group of electronic compounds with nearly same e/a, indicating that the e/a- constant criterion is valid for Ti-Zr-Ni-Cu glass forming system. Meanwhile, the structural correlations between the icosahedron and truncated octahedron clusters （Zr2Cu） can be considered as a structural model to describe the polymorphous transformation from quacrystals or metallic glass to Zr2Cu-type phase.