Formation of the lamellar structure in Group IA and IIID iron meteoritesAnalytical EM, light microscopy, and electron microprobe analysis are used to study the lamellar plessite structure of Group IA and IIID iron meteorites. The alpha lamellae in IIID structures contained a compositional gradient from 6.1 + or - 0.7 wt pct Ni at the center of the alpha lamellae to 3.6 + or - 0.5 wt pct at the alpha/gamma interface. For the Group IA irons, compositions of 4 wt pct Ni in alpha and about 48 wt pct Ni in gamma are found. Convergent beam electron diffraction was used to characterize the orientation relations at the alpha/gamma interface in the lamellar regions of both Group IA and IIID. The phase transformations responsible for the observed lamellar structure in the IA and IIID chemical groups were also investigated.
Document ID
19890023519
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Kowalik, J. A. (Digital Equipment Corp. Northboro, MA, United States)
Williams, D. B. (Lehigh Univ. Bethlehem, PA, United States)
Goldstein, J. I. (Lehigh University Bethlehem, PA, United States)