中文摘要：

通过计算Cu／Al管氧乙炔气体火焰钎焊条件下形成金属间化合物的各化学反应的熵变，对Cu/Al金属间化合物的形成及向CuAI2转化的趋势进行了化学热力学分析；结合XRD、SEM、EDS研究了Cu／A1管氧乙炔气体火焰钎焊接头组织与元素分布特征。结果表明，Cu／Al管氧乙炔气体火焰钎焊条件下，接头中脆性金属间化合物CuAl2由Cu、Al原子的直接结合和其他Cu／A1金属间化合物与Al原子的继续反应生成，其中CuAl自主转化趋势较强；热力学计算分析与接头XRD分析结果一致。钎焊接头可分为3个特征区域：靠近A1基体侧形成了宽度约30μm的α－Al与α－Al＋CuAl2二元共晶区；钎缝中心偏Al基体一侧形成了宽度约150μm组织细密的多元共晶组织区；钎缝中靠近Cu基体宽度约120μm区域，Cu的大量扩散并与Al充分反应，形成了粗大珊瑚状CuAl。

英文摘要：

Entropy changes in chemical reaction of Cu/A1 intermetallie compounds formation in Cu/A1 oxyacetylene flame brazing are calculated, and the tendency of Cu/AI intermetallic compounds form and transform to CuA12 is analyzed with the method of chemical thermodynamics. The microstructure and characteristics of elements distribution and diffusion of the Cu/A1 oxyacetylene flame brazing joint are analyzed by XRD, SEM and EDS. Results show that, under the condition of Cu/A1 oxyacetylene flame brazing, the CuAI2 intermetallic compounds formed by the direct reaction of Cu＆A1 atoms and the sustained reaction of Cu/A1 intermetallic compounds with A1 atoms. CuA1 has relatively strong independent transformation trend. The results of thermodynamics analysis and calculation are consistent with the XRD of joint. Brazing joint can be divided into three feature regions： the α-A1 and binary euteetic （α-Al＋CuA12） region is near A1 side with the width of about 30 μm; the fine multiple eutectic structure is formed in brazing seam center near A1 side with the width of about 150μm; and the region near Cu substrate with the width of about 120 μm, where Cu diffuses largely and reacts richly with A1 and massive CuAl2 is formed like corals.