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This synopsis was prepared by Oak Ridge National Laboratory for the All-domain Anomaly Resolution Office (AARO). It reports on an analysis of drill shavings and a small bulk piece from a metallic specimen claimed to be linked to an unidentified phenomenon over central Ohio around 1995. Chemical assays, microscopy, computed tomography and gamma spectroscopy showed a conventional near-eutectic aluminum-silicon casting alloy that had cooled slowly and gave off no radiation. The report concludes the specimen is ordinary terrestrial industrial metal with no evidence of exotic origin.
Synopsis: Analysis of a Aluminum Specimen8 Figure 7. Gamma spectroscopy of metal flakes. Energy emission (keV) plotted vs total counts plotted for one of the metal flakes. The spectra show no emission above background across the range of energies. 3.5 Comparison to industry standards — When compared to catalog grades, the sample best matches A413.1 and 369.1 (with similarities to 361.1/365.1/4032 as well). These eutectics are long-established aluminum–silicon casting alloys used across automotive, aerospace, and consumer sectors. Because melts and castings vary by foundry practice, a one‑to‑one element‑by‑element match is not necessary to assign the alloy family. It is common for castings to deviate slightly from catalog numbers depending on melt practice, heat treatment, and the location within a large part. The overall chemistry and microstructure of the sample fall within the expected envelope for these standards. Table 3. Measured alloy composition compared to important industrial standards. Bold text denotes outside the standard specification. Broadly speaking, silicon content is most informative of alloy identification and intended application, so silicon is emphasized in red. Measured Alloy (reference) A319.0 319.1 319.2 360.2 361.1 A365.1 369.1 A413.1 4032 4047 ASTM B969 ASTM B179 ASTM B179 ASTM B179 ASTM B179 ASTM B179 ASTM B179 ASTM B179 ASTM B211/ B211M MIL‑DTL‑ 32495A Al 86.099 ± 1.663 Balance Balance Balance Balance Balance Balance Balance Balance Balance Balance Cr 0.03 ± 0.003 — — — — 0.2‑0.3 — 0.3‑0.4 — 0.1 max — Cu 0.369 ± 0.019 3‑4 3‑4 3‑4 0.1 max 0.5 max 0.02 max 0.5 max 1 max 0.5‑1.3 0.30 max Fe 0.97 ± 0.075 1 max 0.8 max 0.6 max 0.7-1.1 0.8 max 0.15‑0.20 1.3 max 1 max 1.0 max 0.80 max Ga 0.012 ± 0.002 — — — — — — — — — — Mg 0.298 ± 0.09 0.1 max 0.1 max 0.1 max 0.45‑0.6 0.45‑0.6 0.15-0.60 0.3-0.45 0.1 max 0.8‑1.3 0.10 max Mn 0.198 ± 0.012 0.5 max 0.5 max 0.1 max 0.1 max 0.25 max 0.3‑0.6 0.35 max 0.35 max — 0.15 max Ni 0.029 ± 0.003 0.35 max 0.35 max 0.1 max 0.1 max 0.2‑0.3 — 0.05 max 0.5 max 0.5‑1.3 — Pb 0.044 ± 0.005 — — — — — — — — — — Si 11.902 ± 2.175 5.5‑6.5 5.5‑6.5 5.5‑6.5 9‑10 9.5‑10.5 9.5‑11.5 11‑12 11-13 11.0-13.5 11.0-13.0 Sn <0.01 — — — 0.1 max 0.1 max — 0.1 max — — — Ti 0.025 ± 0.004 0.25 max 0.25 max 0.2 max — 0.2 max 0.10 max — — — — Zn 0.203 ± 0.014 1 max 1 max 0.1 max 0.1 max 0.4 max 0.07 max 0.9 max 0.4 max 0.25 max 0.20 max Others Total 0.5 max 0.5 max 0.2 max 0.2 max 0.15 max 0.15 max 0.15 max 0.25 max 0.15 max Others Each 0.05 max 0.05 max 0.05 max 0.05 max
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Report, from the aaro collection. The PDF is mirrored here; the original link is above. 10 pages are in the text index: search them above, or from the library's search.