Of Monel Alloy / Cu Explosive Composite Rod Combined With Numerical Simulation Analysis Of The Interfacial Microstructure Observation And Recombination Processes

The microstructure of bonding interface of Monel alloy/Cu explosive cladding bar was experimentally investigated, and the whole cladding process of which was numerically simulated in the present work. The conclusions were listed as follows:1. The bonding interface of Monel alloy/Cu explosive cladding bar in three different states and the bilateral matrix along the interface were investigated by OM. The observations indicated that the morphology of Monel alloy/Cu interface presented tiny, regular and continuous sine waves, and the microstructure in the vicinity of interface was elongated and curved with waves along the bonding direction. Wavy interface still exited after the samples' annealing and the crystal structure in fusion zone also became distinct; recrystallized structure within lots of annealed twins can be investigated in copper side, while the fibrous structure in Monel alloy was a little slack down. After exposing the swaging process on the annealing samples, the interface waves turned a bit flat, and the annealed structure within fusion region was also smashed. Broken recrystallized crystals and the distinct deformed streamline structure can be investigated in copper and Monel alloy side, respectively.2. The microstructure in the bonded zone of Monel alloy/Cu interface was investigated by TEM. And the results showed that the bonding zone consisted of melting region, heat affected region and deformed region characterized by microbands. The melting region was composed by the amorphous and microcrystal consisting of Cu and Ni, which further demonstrated the metallurgical bonding of explosive cladding. Microcrystal and recrystallized structure composed the heat affected region. The deformed twins and dislocation structure within bilateral strongly-deformated structure existed in Monel alloy and Cu matrix.3. The process of Monel alloy/Cu explosive cladding bar and some phenomena (such as: wavy interface and jetting) characterized by explosive welding were successfully simulated with nonlinear explicit dynamic software AUTODYN. Numerical results showed that: the whole cladding process and the formation of jetting and wavy interface were reproduced; the distribution of dynamic parameters in collision point region was corresponded with calculation results; a very thin layer of severely-shear-deformed zone close to the bonding interface can be illustrated by the distribution of strain and strain rate in collision region; the temperature distribution illustrated the cladding a metallurgical bonding process; all of which were completely coincided with the experimental observations. Moreover, the maximum pressure located in the central axis of copper bar in the earlier stage, and then gradually transferred into the collision point till the stable stage.