Development of Biaxial Tensile Test System for <i>In-situ</i> Scanning Electron Microscope and Electron Backscatter Diffraction Analysis

Effect of Microstructure Variation on Differential Hardening Behavior of Steel Sheets under Biaxial Tensile State

“…The IPF maps show that the grains with near {111} plane orientations in ND tend to rotate to {111} plane orientations with the progress of deformation (e.g., circled grain) and the more obvious development of texture in ND occurs in biaxial deformation, while the development of the {111} plane texture is not seen in the uniaxial test. These results have been verified in our previous study 27) by the measurement of texture with X-ray diffraction for the Marciniak-type macroscopic biaxial tensile test. 30) The previous measurement showed that the maximum intensity of {111} orientation increased with strain.…”

“…The work hardening behaviors are examined first by conventional uniaxial tensile and bulge tests. Next, using the experimental system of in-situ observation and analysis for biaxial tensile deformation by means of electron back scatter diffraction (EBSD) patterns 25,26) with scanning electron microscope (SEM), which was developed in our previous study, 27) the microstructure variations in uniaxial and biaxial deformation states are examined. The effect of texture development on the yield locus is investigated using the TBH theory and ODF, referring to the study by Van houtte.…”

“…Figure 2 shows the experimental system for the tests with in-situ SEM-EBSD analysis developed in our previous study. 27) Here, we briefly explain the test system again. The size of the apparatus is 166 mm in length, 140 mm in width and 42 mm in height, owing to the limitation of space in the vacuum chamber of field emission SEM (FE-SEM).…”

“…The shape and dimensions of specimen were determined from FEM. 27) The specimens were cut from the sheets by a wireelectrical discharge machine. The X shaped reduction area (Fig.…”

Influence of Strain Ratio on Surface Roughening in Biaxial Stretching of IF Steel Sheets

“…In our previous study, therefore, surface roughening and the change of microstructure of IF steel sheets during biaxial tension deformation were examined in detail using two types of tests. One was a macroscopic Marciniak type test 21) and the other was a microscopic biaxial tensile test developed by the authors, 22,23) which enables in-situ continuous observations of sheet surface during biaxial deformation, using a scanning electron microscope/electron backscattered diffraction pattern (SEM/EBSD) method. The results showed that not only the grain size but also the texture of the sheet has a great influence on surface roughening, and that surface roughening became large for sheets which had a large number of crystal grains with orientations in the vicinity of normal direction (ND) (001), due to inhomogeneous deformation derived from their lower deformation resistance.…”