TY - JOUR
T1 - In-Situ Nuclear Magnetic Resonance Investigation of Strain, Temperature, and Strain-Rate Variations of Deformation-Induced Vacancy Concentration in Aluminum
AU - Linga Murty, K.
AU - Detemple, K.
AU - Kanert, O.
AU - Hosson, J.Th.M. De
N1 - Relation: http://www.rug.nl/research/zernike/
Rights: University of Groningen, The Zernike Institute for Advanced Materials
PY - 1998
Y1 - 1998
N2 - Critical strain to serrated flow in solid solution alloys exhibiting dynamic strain aging (DSA) or Portevin–LeChatelier effect is due to the strain-induced vacancy production. Nuclear magnetic resonance (NMR) techniques can be used to monitor in situ the dynamical behavior of point and line defects in materials during deformation, and these techniques are nondestructive and noninvasive. The new CUT-sequence pulse method allowed an accurate evaluation of the strain-enhanced vacancy diffusion and, thus, the excess vacancy concentration during deformation as a function of strain, strain rate, and temperature. Due to skin effect problems in metals at high frequencies, thin foils of Al were used and experimental results correlated with models based on vacancy production through mechanical work (vs thermal jogs), while in situ annealing of excess vacancies is noted at high temperatures. These correlations made it feasible to obtain explicit dependencies of the strain-induced vacancy concentration on test variables such as the strain, strain rate, and temperature. These studies clearly reveal the power and utility of these NMR techniques in the determination of deformation-induced vacancies in situ in a noninvasive fashion.
AB - Critical strain to serrated flow in solid solution alloys exhibiting dynamic strain aging (DSA) or Portevin–LeChatelier effect is due to the strain-induced vacancy production. Nuclear magnetic resonance (NMR) techniques can be used to monitor in situ the dynamical behavior of point and line defects in materials during deformation, and these techniques are nondestructive and noninvasive. The new CUT-sequence pulse method allowed an accurate evaluation of the strain-enhanced vacancy diffusion and, thus, the excess vacancy concentration during deformation as a function of strain, strain rate, and temperature. Due to skin effect problems in metals at high frequencies, thin foils of Al were used and experimental results correlated with models based on vacancy production through mechanical work (vs thermal jogs), while in situ annealing of excess vacancies is noted at high temperatures. These correlations made it feasible to obtain explicit dependencies of the strain-induced vacancy concentration on test variables such as the strain, strain rate, and temperature. These studies clearly reveal the power and utility of these NMR techniques in the determination of deformation-induced vacancies in situ in a noninvasive fashion.
KW - SOLIDS
KW - NACL
U2 - 10.1007/s11661-998-0168-0
DO - 10.1007/s11661-998-0168-0
M3 - Article
VL - 29
SP - 153
EP - 159
JO - Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science
JF - Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science
SN - 1543-1940
IS - 1
T2 - Symposium on Fundamentals of Gamma Titanium Aluminides at the TMS Annual Meeting
Y2 - 10 February 1997 through 12 February 1997
ER -