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本文用X射线衍射的方法全面地研究了Cu-Au二元系合金经不同时间(一个月、三个月、六个月、一年)熟炼后缓冷到室温,以及在300℃和600℃淬炼后的物相与相转变过程;精确地测定了点阵间隔,以研究其随成份和热处理的变迁;探讨了长周期超结构的堆垜周期同成份和温度的关系;并用保持不同热处理时间后淬炼的方法来研究等原子成份处的有序化过程。 在上述的热处理条件下,整个二元系共出现了六种不同的相:α_1是Au在Cu中的固溶体,α_1~′是相当于Cu_3Au的超结构,α_2是Cu在Au中的固溶体,α_2~′是相当于CuAu_3的超结构,k是相当于CuAuⅠ的超结构,k′是相当于CuAuⅡ的超结构。值得注意的是,随着热处理时间的加长,有序区逐渐扩大,二相区逐渐缩小,在一年缓冷的合金,二相区几乎完全消失。因此作者认为:Cu-Au系的二相共存是处于介稳状态,以α_2~′相而论,最清晰的超结构线并不出现在化学计量成份而在68at.%Au。在等原子成份两边所出现的k′相,当合金经一年熟炼之后,一部分又变成了k相,在等原子成份处,k相和k′相的最高转变温度都并不恰好在等原子成份,而在于或小于49at.%Au。 点阵间隔的量度表明:基本单胞平均点阵间隔同成份的关系是正偏离Vegard定律的连续曲线。在α和α′相区内,α值随Au含量而递增。在Au含量小于等
In this paper, by X-ray diffraction method fully studied Cu-Au binary system alloy at different times (one month, three months, six months, a year) cooked slowly cooled to room temperature, and 300 ℃ and 600 ℃ after quenching the phase and phase transformation process; precise determination of the lattice spacing to study its composition and heat treatment changes; discussed the long-period super-structure stacking cycle with the composition and temperature of the relationship; and with different The heat treatment time after quenching method to study the atomic ordering of atoms at the process. Under the above heat treatment conditions, six different phases appeared in the whole binary system: α_1 is the solid solution of Au in Cu, α_1 ~ ’is the superstructure of Cu_3Au, α_2 is the solid solution of Cu in Au, and α_2 ~ ’Is a superstructure corresponding to CuAu_3, k is a superstructure corresponding to CuAuI, and k’ is a superstructure equivalent to CuAuII. It is noteworthy that, with the extension of heat treatment time, the orderly area gradually expanded, two-phase area gradually reduced in one year slowly cooled alloy, two-phase area almost completely disappeared. Therefore, the authors believe that the coexistence of the two phases in the Cu-Au system is in a metastable state, and the clearest super-structure line does not appear in the stoichiometric composition at 68 at% Au. The k ’phase appearing on both sides of the equiatomic component, when the alloy is refined after a year, some of them become k phase again. At the same atomic composition, the highest transition temperatures of k phase and k’ phase are not exactly equal Atomic composition, but at or below 49 at.% Au. The measurement of lattice spacing shows that the relationship between the average lattice spacing of basic unit cells and the composition is a positive curve deviating from Vegard’s law. In the α and α ’phase regions, the value of α increases with the Au content. The content of Au is less than or equal