TY - JOUR
T1 - The effect of size on the strength of FCC metals at elevated temperatures
T2 - annealed copper
AU - Wheeler, Jeffrey M.
AU - Kirchlechner, Christoph
AU - Micha, Jean-Sébastien
AU - Michler, Johann
AU - Kiener, Daniel
PY - 2016/12/1
Y1 - 2016/12/1
N2 - As the length scale of sample dimensions is reduced to the micron and sub-micron scales, the strength of various materials has been observed to increase with decreasing size, a fact commonly referred to as the ‘sample size effect’. In this work, the influence of temperature on the sample size effect in copper is investigated using in situ microcompression testing at 25, 200 and 400 °C in the SEM on vacuum-annealed copper structures, and the resulting deformed structures were analysed using X-ray μLaue diffraction and scanning electron microscopy. For pillars with sizes between 0.4 and 4 μm, the size effect was measured to be constant with temperature, within the measurement precision, up to half of the melting point of copper. It is expected that the size effect will remain constant with temperature until diffusion-controlled dislocation motion becomes significant at higher temperatures and/or lower strain rates. Furthermore, the annealing treatment of the copper micropillars produced structures which yielded at stresses three times greater than their un-annealed, FIB-machined counterparts.
AB - As the length scale of sample dimensions is reduced to the micron and sub-micron scales, the strength of various materials has been observed to increase with decreasing size, a fact commonly referred to as the ‘sample size effect’. In this work, the influence of temperature on the sample size effect in copper is investigated using in situ microcompression testing at 25, 200 and 400 °C in the SEM on vacuum-annealed copper structures, and the resulting deformed structures were analysed using X-ray μLaue diffraction and scanning electron microscopy. For pillars with sizes between 0.4 and 4 μm, the size effect was measured to be constant with temperature, within the measurement precision, up to half of the melting point of copper. It is expected that the size effect will remain constant with temperature until diffusion-controlled dislocation motion becomes significant at higher temperatures and/or lower strain rates. Furthermore, the annealing treatment of the copper micropillars produced structures which yielded at stresses three times greater than their un-annealed, FIB-machined counterparts.
KW - copper
KW - high temperature deformation
KW - Size effect
KW - µ-Laue diffraction
UR - http://www.scopus.com/inward/record.url?scp=84984670356&partnerID=8YFLogxK
U2 - 10.1080/14786435.2016.1224945
DO - 10.1080/14786435.2016.1224945
M3 - Article
AN - SCOPUS:84984670356
SN - 1478-6435
VL - 96.2016
SP - 3379
EP - 3395
JO - Philosophical magazine
JF - Philosophical magazine
IS - 32-34
ER -