Characterization of Shear Bands in Ultrafine-grained Commercial Purity Aluminum

• Main Authors: Hung-chia Chu, 朱宏加
• Other Authors: Chih-Pu Chang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/68132153902385734212

碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 100 === In this study, ultrafine-grained commercial purity AA1050 aluminum was produced by equal channel angular extrusion (ECAE).Annealing at 250℃ was able to give a grain size of 0.59μm. Specimens were compressed along different ECAE axis under a strain rate of 7.1×10-4 s-1at room temperature. Compression tests were also performed under 5×10-5 s-1, 7.1×10-4 s-1 ,and 10-1 s-1 strain rates at 100℃,150℃ ,and 175℃. Surface morphology of specimens was observed by optical and scanning electron microscopes to study the generation of shear bands. Texture within shear bands was analyzed by electron backscattered diffraction (EBSD). The present research found that, different compression direction has little effect on the generation of shear bands. Increasing compression temperature and decreasing strain rates have the effect of decreasing the degree of strain localization of shear bands. Shear band deformation is compatible with the uniform deformation occurred outside shear bands. Texture change within shear bands is rotated about an axis perpendicular to the specimen surface, and strengthens the texture component.