| In the early20th century, it was proposed to add ceramic particles to the metal, in order to obtain a new type of composite with the strength of ceramic materials and plasticity of metal materials. And this new type of composite received widespread attention, among which B4C reinforced Al matrix composite has been widely used in the areas of light protection and bulletproof armor. Besides, ceramic plate composited with metal is of great importance in the area of bulletproof armor because of the high hardness in ceramic layer and high toughness modulus in the metal layer offer excellent advantages. Nevertheless, the stripping between the ceramic plate and metal back layer needs to be considered. In this paper, a new type of laminated composite with B4C reinforced Al matrix composites as its inner layer and metal Al as the outer layer was fabricated. Obviously, it has extraordinary advantages:on the one hand, it combines the advantages of B4C particle reinforced Al matrix composite and Al/B4C clad material, meeting armored requirement as a result. On the other hand, the matrix phase is continuous; therefore, layer interface is continuous. In addition, it has broad prospects for development attribute to its good toughness and weld ability of outer layer.The purpose of this paper is to prepare Al/B4C metal-metal ceramic laminated composites, for which powder metallurgy method was used to explore how the performances were influenced by experimental parameters (e.g., the components of the inner layer, pressing force etc.). It was shown that in the experimental conditions (hot pressing temperature:100-300℃, pressure:50-150MPa, the mass fraction of Al in the inner layer:30%,40%,50%,60%,70%respectively), the samples with more than50%wt-Al in the inner layer can be well formed. Furthermore,57.64%,60.56%,62.36%,65.27%wt-Al in the inner layer were selected according to the golden section method, among which62.36%wt-Al experienced the highest average micro Vickers hardness. The deformation rates of samples were influenced most by hot pressing force, then came component of inner layer, hot pressing temperatures and holding time contributed least to deformation rates.Besides, the combination of static semi-continuous casting experiment and hot rolling was adopted to fabricate this new type of laminated composite, and the analysis was mainly about micro structure, composition distribution and mechanical properties. Some conclusions can be drawn:Firstly, there was a pressure difference between the Al alloy melt outside the baffle and the mixed powder inside, so extra pressure should be applied to the powder; Secondly, the matrix phase was continuous from the outer layer and the inner layer and the B4C particles distribution was uniform. Thirdly, the micro Vickers hardness witnessed a gradual decrease from the middle of the inner layer to the outer layer before a hardness dropping transition region near the intermediate layer, and then remained stable in the outer layer. In addition, an element diffusion layer approximately3micrometers wide was formed between B4C particle and Al, and a full diffusion between the Al matrix was also achieved, proving a good metallurgical bond was obtained between inner layer and outer layer. The results above showed that laminated composites with fine binding and good performance can be fabricated via the combination of semi-continuous casting and hot rolling process. |
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