Asynchronous Stack Rolling Preparation Of Ultrafine Grained Copper Deformation And Organization

Grain refinement is the effective method to improve copper's properties. Severe plastic deformation with Asymmetrical Accumulative Roll-bonding(AARB) has strong ability to refine grain. It is superior to the traditional pile rolling, and greatly improves the precision rolling method of the products. So AARB has a good prospect. The paper has adopted the method of AARB to prepare the ultra-fine grain of copper materials.This paper studied the process of preparing the ultra-fine grain of copper materials by the method of AARB. Utilizing the analysis methods of Optical Microscopy, Scan Electron Microscopy, X-ray Diffraction, and other mechanical properties testing, we have studied the microstructure's change in the rolling process of pure copper, the effect of cumulative deformation on sample's structure after annealing and the effect of annealing system on the microstructure of materials. The samples mechanical performances were tested and analyzed in different annealing system.The studies showed that:1. After AARB, there is cold deformation texture on(111) and(200) planes. After recrystallization annealing the texture is still in the recrystallization microstructure.2. The favorable true strain of preparing the ultra-fine grain of copper materials by the method of AARB is 3.93(the amount of deformation after six passes) The appropriate annealed temperature is 260℃×60min, on this temperature we can get the ultra-fine grain of 3～5μm. We can also get the ultra-fine grain of 5μm at 380℃×5min.3. The mechanical properties of copper materials with ultra-fine grain is good. The tensile strength is 256.4MPa.The elongation is 31%. The hardness is 70.56HV.