对采用严重塑性变形方法制备的超细晶金属进行退火处理,是提高该类材料综合性能的常见方法.为保证晶粒不发生明显长大,对累积叠轧(ARB)方法制备的超细晶纯铜在100℃(低于再结晶温度)时进行退火处理,研究保温时间对ARB超细晶铜室温拉伸断裂行为的影响以及样品的微观结构、力学行为、断口形貌,并对其力学性能和断裂机制进行分析.结果表明:当退火时间为30 min时,ARB超细晶铜的屈服强度和抗拉强度都达到退火态的极大值.断口的大量韧窝表明:退火时间30 min时的材料具有一定的塑性变形能力,断裂机制以韧性断裂为主,因此,退火时间为30 min时,ARB超细晶铜的强度与塑性达到最佳匹配.%Preparing ultrafine grained (UFG) materials by annealing treatment is a common method to improve the plasticity of severe plastic deformation (SPD) materials. The ultrafine grained pure Cu prepared by accumulative rolling bonding (ARB) method at 100 ℃ (below the recrystallization temperature) was annealed in order to ensure that the grain does not grow obviously. The effect of different holding time on the tensile deformation behavior of ARB-Cu at room temperature was investigated. The microstructures, the fracture morphologies and the mechanical curves of ARB-Cu were analyzed, the mechanical property and the microscopic fracture mechanism were discussed. The results show that, when the annealing time is 30 min, the yield strength, the tensile strength and the plastic all reach the maximum of the annealed states. The number of dimple can be known that it has certain plastic deformation ability, the fracture mechanism is ductility fracture. In conclusion, the strength and plasticity of the annealing time 30 min reach the best match.
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