On the extraction of yield stresses from micro-compression experiments

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:800

Article

Purstl, J. T.¹  Jones, H. O.^1,2  Edwards, T. E. J.^1,3  Thompson, R. P.¹  Di Gioacchino, F.^1,4  Jones, N. G.¹  Clegg, W. J.¹ 

[1] Univ Cambridge, Dept Mat Sci & Met, 27 Charles Babbage Rd, Cambridge CB3 0FS, England

[2] Univ Oxford, Dept Mat, Parks Rd, Oxford OX1 3PH, England

[3] Swiss Fed Labs Mat Sci & Technol, Empa, Lab Mech Mat & Nanostruct, Feuerwerkerstr 39, CH-3602 Thun, Switzerland

[4] Colorado Sch Mines, Dept Met & Mat Engn, ASPPRC, 1500 Illinois St, Golden, CO 80401 USA

关键词: Micropillar compression;    Digital image correlation;    Plasticity;    Critical resolved shear stress;   

DOI  :  10.1016/j.msea.2020.140323

来源: Elsevier

【 摘 要 】

It is widely stated that yield stress extraction from micro-compression testing can be unreliable due to factors such as the pillar taper, pillar-punch misalignment and lateral displacement for example through discrete slip events. This study reports on how these factors can be eradicated when using digital image correlation based strain mapping. This approach is demonstrated through a conventional micropillar compression experiment using the hexagonal MAX phase system Cr2AlC. The use of this approach enables the uncertainty of the extracted yield stress values to be significantly reduced and effectively increases the precision of critical resolved shear stress extraction for basal plane slip from +/- 52% to +/- 4% of the mean value. The findings suggest that the statistical variations commonly observed in micro-compression tests may frequently be linked to systematic errors in the stress measurements taken, and that precise evaluation of deformation statistics can only be facilitated if the pillar deformation morphology is closely monitored.

【 授权许可】

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