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Asymmetric Cryorolling For Fabrication Of Nanostructural Aluminum Sheets, Hailiang Yu, Cheng Lu, K. Tieu, Xianghua Liu, Yong Sun, Qingbo Yu, Charlie Kong
Asymmetric Cryorolling For Fabrication Of Nanostructural Aluminum Sheets, Hailiang Yu, Cheng Lu, K. Tieu, Xianghua Liu, Yong Sun, Qingbo Yu, Charlie Kong
Faculty of Engineering - Papers (Archive)
Nanostructural Al 1050 sheets were produced using a novel method of asymmetric cryorolling under ratios of upper and down rolling velocities (RUDV) of 1.1, 1.2, 1.3, and 1.4. Sheets were rolled to about 0.17 mm from 1.5 mm. Both the strength and ductility of Al 1050 sheets increase with RUDVs. Tensile strength of Al sheets with the RUDV 1.4 is larger 22.3% of that for RUDV 1.1, which is 196 MPa. The TEM observations show the grain size is 360 nm when the RUDV is 1.1, and 211 nm for RUDV 1.4.
Study Of Vacancy-Type Defects By Positron Annihilation In Ultrafine-Grained Aluminum Severely Deformed At Room And Cryogenic Temperatures, L H. Su, Cheng Lu, Lizi He, L C. Zhang, P Guagliardo, A K. Tieu, S N. Samarin, J F. Williams, H J. Li
Study Of Vacancy-Type Defects By Positron Annihilation In Ultrafine-Grained Aluminum Severely Deformed At Room And Cryogenic Temperatures, L H. Su, Cheng Lu, Lizi He, L C. Zhang, P Guagliardo, A K. Tieu, S N. Samarin, J F. Williams, H J. Li
Faculty of Engineering - Papers (Archive)
"Commercial-purity aluminum was processed by equal-channel angular pressing (ECAP) at room temperature (RT-ECAP) and cryogenic temperature (CT-ECAP) with liquid nitrogen cooling between two successive passes.It was found that the RT-ECAPed samples showed equiaxed microstructure after 4 and 8 ECAP passes, while the CT-ECAPed samples displayed slightly elongated microstructure and slightly smaller grain size.Moreover, the CT-ECAPed samples had higher hardness values than the RT-ECAPed samples subjected to the same amount of deformation.Positron annihilation lifetime spectroscopy (PALS) was used to investigate the evolution of vacancy-type defects during the ECAP deformation process.The results showed that three types of defects existed in the ECAPed …