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采用固-液复合法制备纯铜-纯铝复合材料。利用光学显微镜、XRD、SEM、EDS、显微硬度计和拉压万能试验机等手段研究结合界面的微观组织、相组成、成分分布、力学性能及断口特征。结果表明,在700℃下,可实现铜铝的固液复合,界面平整,存在一定宽度的过渡层,有元素互扩散现象。在界面生成CuAl_2、CuAl、Cu_9Al_4、CuAl_3、CuAl_4等多种金属间化合物或固溶体。Cu-Al结合界面的宽度随退火温度升高而增加,生成的中间相因相互反应而减少,界面结合强度则逐渐增大。直接复合的结合强度为29.9 MPa,经200℃×2 h和400℃×2 h退火处理后的界面结合强度则分别为59.1 MPa和74.1 MPa。直接复合的断裂方式为偏向韧性的准解理断裂,断口凹凸不平,出现少量撕裂棱,经退火处理后发生典型的脆性断裂,断口出现明显的解理台阶及大量撕裂棱。提出铜/铝复合界面主要包括富铜区,富含金属间化合物的过渡区、富铝凝固区和富铝区4个区域。
Preparation of Pure Copper - Pure Aluminum Composites by Solid - liquid Composite Method. The microstructure, phase composition, composition distribution, mechanical properties and fracture characteristics of the bonded interface were studied by means of optical microscope, XRD, SEM, EDS, microhardness tester and tensile universal testing machine. The results show that at 700 ℃, solid-liquid composite of copper and aluminum can be achieved, the interface is smooth, there is a transition layer with a certain width, and there is element mutual diffusion phenomenon. In the interface CuAl_2, CuAl, Cu_9Al_4, CuAl_3, CuAl_4 and other intermetallic compounds or solid solution. The width of the Cu-Al bonding interface increases with the annealing temperature, and the intermetallic phase decreases due to the mutual reaction, and the bonding strength increases gradually. The bonding strength of direct composites is 29.9 MPa, and the interfacial bonding strength after annealed at 200 ℃ × 2 h and 400 ℃ × 2 h is 59.1 MPa and 74.1 MPa, respectively. The direct composite fracture mode is the biased cleavage tendencies toward ductile fracture. The fracture surface is uneven with a few tearing edges. The typical brittle fracture occurs after annealing treatment, and the cleavage steps show obvious cleavage steps and a large number of tearing edges. It is proposed that the copper / aluminum composite interface mainly includes copper-rich area, transition region rich in intermetallic compounds, four regions rich in aluminum solidification zone and aluminum-rich zone.