TY - JOUR
T1 - An Examination of the Composition and Microstructure of Coarse Intermetallic Particles in AA2099-T8, Including Li Detection
AU - MacRae, Colin M.
AU - Hughes, Anthony E.
AU - Laird, James S.
AU - Glenn, A. M.
AU - Wilson, Nicholas C.
AU - Torpy, Aaron
AU - Gibson, Mark A.
AU - Zhou, Xiaorong
AU - Birbilis, Nick
AU - Thompson, George E.
N1 - Publisher Copyright:
© 2018 Microscopy Society of America.
PY - 2018/8/1
Y1 - 2018/8/1
N2 - Electron and proton microprobes, along with electron backscatter diffraction (EBSD) analysis were used to study the microstructure of the contemporary Al-Cu-Li alloy AA2099-T8. In electron probe microanalysis, wavelength and energy dispersive X-ray spectrometry were used in parallel with soft X-ray emission spectroscopy (SXES) to characterize the microstructure of AA2099-T8. The electron microprobe was able to identify five unique compositions for constituent intermetallic (IM) particles containing combinations of Al, Cu, Fe, Mn, and Zn. A sixth IM type was found to be rich in Ti and B (suggesting TiB 2 ), and a seventh IM type contained Si. EBSD patterns for the five constituent IM particles containing Al, Cu, Fe, Mn, and Zn indicated that they were isomorphous with four phases in the 2xxx series aluminium alloys including Al 6 (Fe, Mn), Al 13 (Fe, Mn) 4 (two slightly different compositions), Al 37 Cu 2 Fe 12 and Al 7 Cu 2 Fe. SXES revealed that Li was present in some constituent IM particles. Al SXES mapping revealed an Al-enriched (i.e., Cu, Li-depleted) zone in the grain boundary network. From the EBSD analysis, the kernel average misorientation map showed higher levels of localized misorientation in this region, suggesting greater deformation or stored energy. Proton-induced X-ray emission revealed banding of the TiB 2 IM particles and Cu inter-band enrichment.
AB - Electron and proton microprobes, along with electron backscatter diffraction (EBSD) analysis were used to study the microstructure of the contemporary Al-Cu-Li alloy AA2099-T8. In electron probe microanalysis, wavelength and energy dispersive X-ray spectrometry were used in parallel with soft X-ray emission spectroscopy (SXES) to characterize the microstructure of AA2099-T8. The electron microprobe was able to identify five unique compositions for constituent intermetallic (IM) particles containing combinations of Al, Cu, Fe, Mn, and Zn. A sixth IM type was found to be rich in Ti and B (suggesting TiB 2 ), and a seventh IM type contained Si. EBSD patterns for the five constituent IM particles containing Al, Cu, Fe, Mn, and Zn indicated that they were isomorphous with four phases in the 2xxx series aluminium alloys including Al 6 (Fe, Mn), Al 13 (Fe, Mn) 4 (two slightly different compositions), Al 37 Cu 2 Fe 12 and Al 7 Cu 2 Fe. SXES revealed that Li was present in some constituent IM particles. Al SXES mapping revealed an Al-enriched (i.e., Cu, Li-depleted) zone in the grain boundary network. From the EBSD analysis, the kernel average misorientation map showed higher levels of localized misorientation in this region, suggesting greater deformation or stored energy. Proton-induced X-ray emission revealed banding of the TiB 2 IM particles and Cu inter-band enrichment.
KW - AA2099 aluminium alloys
KW - Li detection
KW - electron backscatter diffraction
KW - electron microprobe
KW - soft X-ray emission spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85048746954&partnerID=8YFLogxK
U2 - 10.1017/S1431927618000454
DO - 10.1017/S1431927618000454
M3 - Article
SN - 1431-9276
VL - 24
SP - 325
EP - 341
JO - Microscopy and Microanalysis
JF - Microscopy and Microanalysis
IS - 4
ER -