Tubular pure copper grain refining by tube cyclic extrusion–compression(TCEC) as a severe plastic de

来源 :Progress in Natural Science:Materials International | 被引量 : 0次 | 上传用户:LYXTTKX
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Tube Cyclic Extrusion–Compression(TCEC) method is a novel severe plastic deformation technique developed for grain refining of cylindrical tubes to ultrafine grained(UFG)/nanostructured ones. In this method, tubes are fully constrained and deformed between chamber and mandrel with a small neck zone. The principle of TCEC technique which was adopted to impose severe plastic strains to the tubular materials was explained. Also, the deformation and grain fragmentation mechanism during TCEC was analyzed. The material deformation characteristics during TCEC were numerically simulated by FE code of ABAQUS/Explicit. The FEM results demonstrated that TCEC technique was able to impose extremely high plastic strains. The TCEC method was successfully applied to a commercially pure copper(99.99%) and significant grain refinement was achieved. TEM observation demonstrated the refinement of grains from the initial size of 45 μm to 200–350 nm after four processing cycles of TCEC. Microhardness measurements were carried out across the thickness of the initial and processed tubes. The results show good homogeneity of hardness distribution and an increase to 102 Hv from initial value of 55 Hv after four TCEC cycles. Mechanical properties of the specimens were extracted from tensile tests. The obtained results documented notable increase in the yield and ultimate strengths, whereas the uniform and total elongations decreased. Fracture surfaces after tensile tests were investigated by scanning electron microscopy(SEM), and the observed morphology indicates ductile fracture mode after four cycles of TCEC. Tube Cyclic Extrusion-Compression (TCEC) method is a novel severe plastic deformation technique developed for grain refining of cylindrical tubes to ultrafine grained (UFG) / nanostructured ones. In this method, tubes are fully constrained and deformed between chamber and mandrel with a small The principle of TCEC technique was was to impose severe plastic to the tubular materials was explained. Also, the deformation and grain fragmentation mechanism during TCEC was analyzed. The material deformation characteristics during TCEC were numerically simulated by FE code of ABAQUS / Explicit. The FEM results in that TCEC technique was able to impose extremely high plastic strains. The TCEC method was successfully applied to a pure pure copper (99.99%) and significant grain refinement was achieved. TEM showed demonstrated the refinement of grains from the initial size of 45 μm to 200-350 nm after four processing cycles of TCEC. Microhardness m easurements were carried out across the thickness of the initial and processed tubes. The results show good homogeneity of hardness distribution and an increase to 102 Hv from initial values ​​of 55 Hv after four TCEC cycles. Mechanical properties of the specimens were extracted from tensile tests. The resulting results documented notable increase in the yield and ultimate strengths, while the uniform and total elongatedations decreased, even the tensile tests were investigated by scanning electron microscopy (SEM), and the observed morphology shows ductile fracture mode after four cycles of TCEC.
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