The Formation,Evolution And Final Structure Of Interface In Metal Explosive Welding

With the progress of industrial technology, people have newer and higher requirements on material performance, quality and so on. Composite material through the combination of physical, chemical and mechanical properties of different materials has widely used in industrial production. Due to its widely range of weld-able material combinations and the advantage in the variety, size, yield, quality, marketing, and cost-effective so in the manufacture of composite materials the explosive welding cause more and more attention.In the process of explosive welding, the morphology of the weld interface has a significant impact on the quality of welding. At present research on explosive welding are most in the macroscopic and qualitative analysis state of experiment tests, observations, theoretical analysis, and most of these studies are in the explosive welding of different metal. And it is considered that the difference of density between the dissimilar metals to form wavy interface. But for the homogeneous metal explosive welding has less study. In order to promote the formation of the universally applicable explosive welding theory on homogeneous and heterogeneous metal and advance the quantitative analysis of. explosive welding interface. In this paper, were studied the formation, evolution and final structure of homogeneous metal explosive welding interface.By establishing a fluid-plastic-body model to theoretical analysis the formation and the development of interfaces, We obtained no matter the metal is similar or not, the existence of micro gaps(surface defects of tight contact metals) or macro gaps(stand-off between fly plate and basic plate) is the origin of instability, and the thermal softening has formed before the collision of fly plate and base plate because of detonation pressure. The instability occurred due to the difference of density between the thermal softening and air. After the collision between base plate and fly plate,there is a compete between the original disturbance and the liquid metal viscoelastic during solidification.By the observations of SEM experiment,explosive welding interface structure was found with the increase in observe accuracy, the interface has a finer topography, this required statistical methods to quantitatively describe it; and there are many micro-cracks and smooth regional in the interface, micro-cracks reflects the brittle behavior of the material,and the smooth area reflects the toughness behavior of the material.By the three-dimensional depth of field experiment,the central and side region of the interface are observed. The peaks and valleys features are portrayed by the red and blue colors. The peaks and valleys features can observed clearly.After processed the image by the computer, we program the fractal theory to analysis the pixel intensity curve and contour curve of the image, we found the simple fractal characterize the complexity of the interface. The interface in the detonation direction has more complexity than in the vertical direction. Compared with the side region the central region has more complexity degree. By analysis the image using multi-fractal theory, we found multi-fractal characterize the inhomogeneity of interface distribution. The inhomogeneity in central region is large than the side area and so the central region has more complexity degree, this consistent with the results of simple fractal dimension and macro observations.