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利用TEM观察累积叠轧法(ARB)制备的超细晶Cu的微观结构,在IBTC-5000单轴疲劳试验机上对制备态及不同温度退火态的ARB-Cu进行单向静态拉伸实验,通过SEM观察力学测试后试样的断口形貌。结果表明:在实验温度范围内,退火处理均使ARB-Cu的屈服强度和抗拉强度下降,当退火温度低于再结晶温度时,ARB-Cu的屈服强度和抗拉强度均随退火温度的升高而升高;当退火温度高于再结晶温度时,其强度迅速下降。当退火温度为200 ℃时,ARB-Cu的屈服强度和抗拉强度达到退火态最大值。随退火温度的升高,ARB-Cu的晶粒尺寸略微增大,晶粒分布逐渐由制备态的单峰分布转变为双峰分布,断口形貌显示出塑性逐渐增加的趋势。退火处理有助于ARB材料焊合界面结合强度的提高,退火温度越高,焊合界面结合性能越好。焊合界面经历的叠轧道次越多,其结合效率越高,其理论计算公式为E=(1-0.5n)×100%。

Annealing treatment is an effective method for improving structural stability of ultrafine-grained (UFG) or nanostructured (NS) materials produced by severe plastic deformation (SPD). This work focuses on the effect of annealing temperature on the tensile fracture behavior of UFG Cu produced by accumulative roll bonding (ARB). Annealing treatment was performed for 10 min at temperatures of 100, 150, 200 and 250 ℃. The microstructure of annealed and ARBed UFG Cu was observed by TEM. The uniaxial static tensile test was performed by utilizing fatigue testing machine (IBTC-5000) with an initial strain rate of 10-2 s-1. Fracture morphology was observed by SEM. The results suggested that yield strength and tensile strength decreased after annealing treatment compared with initial sample. However, yield strength and tensile strength of ARB-Cu increased with increasing annealing temperature below recrystallization temperature. When annealing temperature is higher than recrystallization temperature, the strength decreased rapidly. With increasing the annealing temperature, the grain size of ARB-Cu increases and gradually tends to bimodal distribution, and the fracture morphology shows a trend of increasing plasticity gradually. The annealing treatment is helpful to bonding efficiency E. The relationship between the theoretical bonding efficiency E and the ARB passes n can be expressed in E=(1-0.5n)×100%.

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