动态塑性变形制备的超细晶铝的热稳定性研究

Thermal Stability of Ultra-fine Aluminum Processed by Dynamic Plastic Deformation

采用分离式霍普金森压杆对1050商业纯铝进行了高应变速率(2.7×10~3s^(-1)变形。试样随后进行100~250℃保温1h的退火。用透射电子显微镜观察了组织。结果表明:变形试样组织主要为拉长的片层状亚晶粒,横向和纵向平均晶粒尺寸分别为276、704nm,原始粗晶粒得到明显细化;当退火温度低于200℃时,试样组织依然为片层状,晶粒稍微粗化;250℃/1 h退火后试样微结构显著粗化,平均晶粒尺寸长大至4.9μm,并且试样组织中出现了再结晶晶粒。为了保持试样组织结构的稳定性,该试样使用温度必须低于250℃。

Abstraet：1050 commercial pure aluminum was subjected to high-strain-rate deformation （2.7×10^3S-1） by split Hopkinson pressure bar （SHPB）. And then the samples were annealed at 100-250℃ for 1 h. The microstructure was observed by transmission electron microscope. The results show that the microstructure of deformed specimen is mainly elongated lamellar subgrains, and the transverse and longitudinal average grain sizes are 276 and 704 nm, respectively. The initial coarse grains are refined significantly. When the annealing temperature is below 200℃, the microstructure of specimens is still lamellar, and grains are slightly coarse. The microstructure of the sample annealed at 200℃ for 1 h is significantly coarse, and the average grain size is 4.9μm. And recrystallization grains occurred in the samples. In order to keep the stability of the specimen microstructure, the use temperature of sample must be lower than 250℃. Key words： dynamic deformation; split Hopkinson pressure bar （SHPB）; lamellar structure; 1050 pure aluminum