Effects of Grain Boundary Constraint on the Constitutive Response of Tantalum Bicrystals.

Ziegler, A. ; Campbell, G. H. ; Kumar, M. ; Stoelken, J. S.

Technical Information Center Oak Ridge Tennessee

关键词: Grain boundaries;    Tantalum;    Crystals;    Compression;    Deformation;   

RP-ID  :  DE200415007724

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

The role of grain boundary constraint in strain localization, slip system activation, slip transmission, and the concomitant constitutive response was examined performing a series of uniaxial compression tests on tantalum bicrystals. Tantalum single crystals were diffusion bonded to form a (011) twist boundary and compressed along the direction. The resulting three- dimensional deformation was analyzed via volume reconstruction. With this, both, the effective states of stress and strain over the cross-sectional area could be measured as a function of distance from the twist boundary, revealing a highly constrained grain boundary. Post-test metallurgical characterization was performed using Electron Back-Scattered-Diffraction (EBSD). The results, a spatial distribution of slip patterning and mapping of crystal rotation around the twist-boundary was analyzed and compared to the known behavior of the individual single crystals. A rather large area near the grain boundary revealed no crystal rotation.