Using the twin shear stress yield criterion, the surface integral of the co-line vectors, and the integration depending on upper limit, Kobayashi＇s three-dimensional velocity field of rolling was analyzed and an anal...Using the twin shear stress yield criterion, the surface integral of the co-line vectors, and the integration depending on upper limit, Kobayashi＇s three-dimensional velocity field of rolling was analyzed and an analytical expression of rolling torque and single force was obtained. Through redoing the same experiment of rolling pure lead as Sims, the calculated results by the above expression were compared with those of Kobayashi and Sims formulae. The results show that the twin shear stress yield criterion is available for rolling analysis and the calculated results by the new formula are a little higher than those by Kobayashi and Sims ones if the reduction ratio is less than 30%.展开更多
The twinning in the intermetallic compound Al18Cr2Mg3 was observed and identified by transmission electron microscopy.The geometric description of the twinning in Al18Cr2Mg3 with 184 atoms per unit cell was investigat...The twinning in the intermetallic compound Al18Cr2Mg3 was observed and identified by transmission electron microscopy.The geometric description of the twinning in Al18Cr2Mg3 with 184 atoms per unit cell was investigated at atomic level.The classical theory of deformation twinning states that the net atomic displacements are divided into shear and shuffles during twinning.Based on the theory and the hypothesis of full mirror reflection symmetry,the displacement and angle of shuffle were calculated for each atom.The geometric calculation results show that all of the atoms in single crystal Al18Cr2Mg3 have to shuffle.Moreover,the calculation results can be divided into 22 groups,which do not show obvious regularity.展开更多
基金ItemSponsored by National Natural Science Foundation of China (50474015)
文摘Using the twin shear stress yield criterion, the surface integral of the co-line vectors, and the integration depending on upper limit, Kobayashi＇s three-dimensional velocity field of rolling was analyzed and an analytical expression of rolling torque and single force was obtained. Through redoing the same experiment of rolling pure lead as Sims, the calculated results by the above expression were compared with those of Kobayashi and Sims formulae. The results show that the twin shear stress yield criterion is available for rolling analysis and the calculated results by the new formula are a little higher than those by Kobayashi and Sims ones if the reduction ratio is less than 30%.
基金financially supported by the 111 Project (No.B08040) of ChinaNational Natural Science Foundation of China (No.51071125)
文摘The twinning in the intermetallic compound Al18Cr2Mg3 was observed and identified by transmission electron microscopy.The geometric description of the twinning in Al18Cr2Mg3 with 184 atoms per unit cell was investigated at atomic level.The classical theory of deformation twinning states that the net atomic displacements are divided into shear and shuffles during twinning.Based on the theory and the hypothesis of full mirror reflection symmetry,the displacement and angle of shuffle were calculated for each atom.The geometric calculation results show that all of the atoms in single crystal Al18Cr2Mg3 have to shuffle.Moreover,the calculation results can be divided into 22 groups,which do not show obvious regularity.
