Study On Producting Copper-Nanostructured Materials By Large Deformation Machining

Machining of large deformation is a new way to produce nano-materials. This method has obvious advantages such as material strength unlimited, the processing parameters easy to control and high efficiency. So many experts and scholars are attention to the application prospects. Based on the theory of metal machining and metal material, The grain refinement mechanism are analyzed by the use of theoretical analysis , finite element simulation and experiments to pure copper.The major creative work and research conclusion of this dissertation were as follows:1. The limitations of currently produceding nano-materials are summarized, and a new way to produce nano-materials is proposed. Then based on the theory of metal machining and metal material, the feasibility of produceding nano-materials by machining is illustrated. It provides theoretical proof for the follow-up analysis of the experimental results.2. Machining experiments are carried out with different tool rake, and the nano-copper grains are obtained. The theoretical analysis are verified and The grain refinement mechanism is analyzed. Also the strain can be increased by controlling the processing parameters such as tool rake, and the greater is the strain, the smaller the grain size, the more uniform, finally to equiaxed nano-grains.3. The machiniing process is simulated by DEFORM-2D finite element method, and in the machiniing process the stress, strain, strain rate and temperature are detailed analysized. The experimental results are verified (ie the shear strain increases with the tool rake decreases, and the very high strain rate can be produced by machining, etc). The relations among the parameters are proposed , it will further enrich and improve parameter control theory of producing nano-materials by machining.Producing copper nanostructured materials by machining is the first time in China, and the results show that nanostructured materials can be produced by machining.This study also enrich and improve the parameters control theory of producing nano-materials by machining. It provide strong technical support for the applications of nanostructured materials by machining...