低浓度Cu-Al_2O_3弥散强化铜合金退火特性的研究

Study of Annealing Characteristics of Low Content Alumina Dispersion Stren gthened Copper Alloy

采用短流程工艺制备了低浓度Cu Al2 O3弥散强化铜合金 ,通过力学性能测量、金相、扫描电镜断口研究了该合金的退火特性。发现该合金 80 %冷轧后进行退火 ,强度和硬度随退火温度的升高不断降低 ,伸长率则不断升高 ,到 4 0 0℃下降和升高速率加快 ,说明合金已发生再结晶 ;退火温度升高到70 0℃以后强度和硬度有所升高 ,而伸长率基本保持不变。组织观察发现 90 0℃退火后的再结晶晶粒比70 0℃的小 ,产生细晶强化 ,强度增量与实验所测增量基本一致 ,并利用回复再结晶理论对其进行了解释 ;合金拉伸断口随着退火温度的升高韧窝尺寸和深度都增加 ,但是 90 0℃韧窝尺寸较 70 0℃的要小。

Low content alumina dispersion strengthened copper alloy was prepared by short-flow technology, and its annealing characteristics was studied by mechanical property measurment, microstructure observation and SEM fracture analysis. The results show that the strength and hardness decrease and elongation increases with the increasing of annealing temperature for the Cu-Al2O3 alloy cold rolled and annealed. The rate of above change increase when annealing temperature reaches 400°C, which indicates that recrystallization has occurred. When annealing temperature is higher than 700°C, the strength and hardness of the alloy increase slightly, while its elongation does not change. The recrystallization grains formed after annealing at 900°C are smaller than that at 700°C, which is explained by recovery-recrystallization theory. Thus, it is deduced that fine-crystal strengthening occurs, and its strength increment calculated by Hall-Petch relationship approaches the experiment value. Fracture surface analysis shows that with the increasing of annealing temperature, the size and depth of dimples increase, but their sizes of annealing at 900°C are smaller than that at 700°C.