Size dependent mechanical behaviour of tantalum

• Published in: International journal of plasticity Vol. 27; no. 3; pp. 470 - 478
• Main Authors: Kaufmann, D., Mönig, R., Volkert, C.A., Kraft, O.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2011; Elsevier
• Subjects: Bcc; BCC metals; Body centered cubic lattice; Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.); Dislocation mobility; Exact sciences and technology; FCC metals; Fundamental areas of phenomenology (including applications); Inelasticity (thermoplasticity, viscoplasticity...); Ion beams; Microcompression; Physics; Size effect; Small scale plasticity; Solid mechanics; Structural and continuum mechanics; Structure of solids and liquids; crystallography; Tantalum; Yield stress; Tantalum; Bcc; Small scale plasticity; Size effect; Microcompression; Sample size; Screw dislocation; Machining; Mobility; Acoustic beam; Experimental study; Compression test; Column; BCC crystals; Focusing; Yield strength
• ISSN: 0749-6419; 1879-2154
• DOI: 10.1016/j.ijplas.2010.08.008

The size dependence of deformation of Ta was studied using compression tests of focused ion beam (FIB) machined microcolumns. Columns with diameters between 0.5 and 8 μm with 〈1 1 1〉 and 〈1 0 0〉 orientations along the column axis were tested. By comparing results of bcc Ta columns with results from previous experiments on fcc metals it was found that Ta shows significantly higher normalized yield stresses in combination with a weaker sample size dependence. The differences between bcc and fcc metals can be attributed to the different dislocation behaviour of bcc metals, especially to the lower mobility of screw dislocations.