PST TiAl samples of different orientations were prepared and deformed by compression at room temperature. The deformation structures on the free surfaces were scanned using an AFM. It was found that when the angle between the lamellar interfaces and the loading axis is between 20 degree and 80 degree, PST samples deform primarily by shear in slip planes parallel to the lamellar interfaces. When the angle is below 20 degree, both the gamma phase and the alpha 2 phase deform by shear in slip planes inclined with the lamellar interfaces, but the shear vectors lie in the interface. When the angle is close to 90 degree, complex deformation behavior occurs. Shear in planes parallel to the lamellar interfaces contributes more to the overall strain in the directions perpendicular to the loading axis and the out-of-plane shear contributes to the strain in the compression direction. The characteristic U-shape curve of the yield stress versus the angle between the loading axis and the lamellar interfaces can be explained quite well using different C.R.S.S. for the three different deformation modes.
This is a preview of subscription content, access via your institution.
We’re sorry, something doesn't seem to be working properly.
Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.
H. Inui, A. Nakamura, M. H. Oh and M. Yamaguchi, Acta. Metall. Mater., 40 (11), 3095 (1992)
Y. Umakoshi, T. Nakano, Acta Metall. Mater., 41, 1155 (1993)
M. Kim, M. Nomura, V. Vitek and D. Pope, in in High-Temperature-Ordered Intermetallic Alloys VIII, edited by E. George, M. Mills, M. Yamaguchi, (Mater. Res. Soc. Symp. Proc. 552, Boston, MA, 1998) pp KK3.1.1
K. Kishida, H. Inui, M. Yamaguchi, Philos. Mag. A, 78 (1) 1 (1998)
Y. Chen, D. Pope, Microscopy Research and Techniques, submitted
Y. Chen, D. Pope, AFM study of the plastic deformation of Polysynthetically twinned (PST) TiAl crystals in hard orientations —— I: A orientation, Acta Mater., to be submitted
Y. Chen, D. Pope, AFM study of the plastic deformation of Polysynthetically twinned (PST) TiAl crystals in hard orientations —— II: N orientation, Acta Mater., to be submitted
H. Inui, M. H. Oh, A. Nakamura, M. Yamaguchi, Philos. Mag. A, 66 (4), 539 (1992)
Lu L, Pope DP, Mater. Sci. and Eng. A, 239–240, 126 (1997)
About this article
Cite this article
Chen, Y., Pope, D.P. Rationalization of the plastic flow behavior of Polysynthetically-twinned (PST) TiAl crystals based on slip mode observation using AFM and Schmid’s law. MRS Online Proceedings Library 842, 435–440 (2004). https://doi.org/10.1557/PROC-842-S6.5