STUDY ON DISSIMILAR METAL BONDING WITH NANO-METER SIZE CRYSTAL INTO BOND INTERFACE AND REACTION AT BOND INTERFACE BY HEAT TREATMENT

利用自行研制的真空辊压焊设备，成功地制备了Al/Ti、Al/Steel、Al/Cu等复合材料。研究了轧制压下量和键合温度对这些复合材料的键合强度、异种金属间键合界面的光学显微组织和高分辨透射电镜结构的影响。并观察了热处理后异种金属间结合界面组织的变化。主要结果如下。(1)复合材料的抗拉强度随压下量和结合温度的增加而增加。(2)用透射电镜观察到非晶、纳米晶结构和金属间化合物的薄层结构。(3)真空辊压粘结方法的粘结机理如下所述。复合材料中较软的金属与较硬的金属相比在结合过程中被拉长，在结合界面处产生摩擦热。键合后，键合界面突然冷却，形成非晶和纳米晶。(4)热处理后，金属间化合物在扩散控制下长大。

We made clad materials such as Al/Ti, Al/Steel and Al/Cu using the vacuum roll bonding apparatus developed by us. Effects of roll reduction and bond temperature on bond tensile strength of these clad materials, optical microstructures and high resolution TEM structures on the bond interfaces between dissimilar metals have been investigated. And also, changes of microstructure on the bond interface between the dissimilar metals have been observed after heat treatments. Main results obtained are as follows. (1) Bond tensile strength of these clad materials increased with increases of reduction and bond temperature. (2) Amorphous, nano-meter crystal structure and inter-metallic compounds in very thin thickness were observed using TEM. (3) The bond mechanism of the vacuum roll bonding method is considered as below. The softer metal composed the clad material is elongated largely compared with the harder metal during the bonding and friction heat is generated at the bond interface. The bond interface is abruptly cooled and the amorphous and nano-meter crystal are formed after bonding. (4) Inter-metallic compounds grew up accordingly by the diffusion controlled after heat treatments.