Study On Mechanism And Process Of Forming And Growing Of Metal Fiber Sintered Crunode

Porous metal fiber materials, which is a new kind of structural and functional material with excellent properties developed by advanced industrial countries in the last20years. Not only does the material have the advantages of stable pores, processable and weldable etc., but also it exhibits large amount of holding dust, folded softly, pore structure designed freedom, so it can be widely used in the fields of filtration and separation, sound absorption and noise reduction, damping, high efficient combustion, electronic magnetic shielding and heat transfer enhanced and so on. The three key components of pore, crunode, fiber skeleton forming microstructure are the basis of integration and diversification of structure and function of porous metal fiber materials. However, the theoretical study on the material is unsubstantial. At present, great attention has been paid to the structure and the mechanical performance of porous metal fiber materials, but a few investigations focuses on the mechanism and process of forming and growing about the crunode. In addition, the crunode is the most key component affecting the structure and the properties, so it has important academic value to study the mechanism of forming and growing of crunode.In this paper, the316L fiber was used as raw material and the effects of hydrogen sintering technology and microwave sintering on the process of forming and growing of the crunode were analyzed. Furthermore, the crunode was reconstructed using the SR-CT technique and VGstudio software and the transferred mechanism was discussed and the neck growing equation was built. At last, the effect of the microwave sintering process on the grain size was studied by SEM.The results obtained are as follows:1. The main diffusion mechanism of stainless steel fiber during high temperature sintering is grain boundary diffusion. 2. The neck-growth equation based on grain boundary diffusion mechanism can be expressed by3. During the sintering process, the grain boundary diffusion coefficient is the order of10-9-10-8, but the holding time and the fiber angels are having few influences on the coefficient.4. The grain size of the316L fiber sintered by microwave sintering process is smaller than that by hydrogen at the same sintering process and the biggest difference is about5.82μm.The work is supported by the National Natural Science Foundation of China (51134003) and the National Basis Research Program of China (2011CB610302) and finished in State Key Laboratory of Porous Metal Materials of Northwest Institute for Nonferrous Metal Research.