Cu/Al复合材料退火过程中的界面组织演变

Interfacial microstructure evolution of Cu/Al composites during annealing

采用轧制复合法制备了Cu/Al复合板,并在350~450℃进行退火处理,利用金相显微镜、扫描电镜、能谱分析仪、X射线衍射仪等手段研究了Cu/Al界面的微观组织形貌和相组成。结果表明,Cu/Al界面扩散连接过程主要包括物理结合、金属间化合物形核、金属间化合物横向生长与增厚3个阶段,Cu/Al界面主要由Cu9Al4、CuAl、CuAl23种金属间化合物组成。金属间化合物形核需要一定的孕育期,孕育期受温度影响很大;金属间化合物层厚度与反应时间的关系符合抛物线规律,表明金属间化合物的生长动力学由体扩散控制;总金属间化合物层生长速率常数与反应温度之间满足Arrhenius关系,其生长激活能为119.08 kJ/mol。

The Cu/Al composite laminates were fabricated by roll bonding,and annealed in the temperature range of 350-450 ℃. The microstructures and phases in the interface were investigated by optical microscope（ OM）,scanning electron microscope（ SEM）,energy dispersive X-ray spectrometer（ EDS）,X-ray diffractometer（ XRD）. The results show that the Cu/Al interface is composed of three intermetallic compound（ IMC） layers,i. e.,Cu_9Al_4,CuAl and CuAl_2 phases,and its bonding process involves three stages,including physical contacting,IMC nucleation,and connection along the interface and continuous thickening of the IMC layer. There is an inculcation time before IMC layer appeared,which is mainly affected by annealing temperature. The relationship of the total IMC layer thickness and annealing time follows the approximate parabolic law,indicating that the growth kinetics of the IMC layer is controlled by the volume diffusion. The growth rate constant of the total IMC layer conforms to the Arrhenius relation with temperature,and the calculated active energy for the IMC layer is 119. 08 kJ/mol.