ADVANCED MATERIALS & PROCESSES | MAY/JUNE 2025 24 TABLE 1 — NONINVASIVE FORENSIC METALLURGY IN ARCHAEOLOGY AND AEROSPACE Procedures Archaeology Aerospace Background information (as much as is available) • Artifact and object descriptions; alloys • Burial sites and types, e.g., cemeteries, hoards • Soil compositions; aerobic or anaerobic conditions • Geographical and geological locations • Cultural areas, periods, chronology • Contemporary mining and smelting sites; smelting techniques and ores • Component descriptions and functions; alloys, fabrication, joining processes, heat-treatment, finishing processes; mechanical properties; service stresses and environments • Dysfunctions or failures and subsequent events; any precursor abnormal events • Service duration (life); monitoring, inspection and maintenance details • Any repairs, replacements, previous problems and remedial actions On-site actions and later in laboratories • Color photographs and documentation • p/l XRF artifact surface analyses • p/l pH, Cl—, redox potentials of soils • Color photographs and documentation • Lightly clean (soft brushes) and dry • Handle and package pieces and relevant debris carefully and separately Nondestructive inspection and purposes • Visual examination and color photography • Stereo binocular microscopy and photography: surface details • XRF patina compositions, detection of primary alloying elements • X-radiography, CT scanning; (both exceptional) for internal damage and cracking • SEM microscopy and fractography of nominally clean jewelry and coins • Visual examination and (color) photography: fracture surfaces, exterior surface qualities, damage and discontinuities, possible defects • Stereo binocular fractography and surface details, color photography • Surface crack detection: e.g., eddy current, fluorescent penetrant, magnetic particle • Internal crack or defect detection: e.g., x-radiography, acoustic emission • SEM microscopy and fractography of small and nominally clean components Key: p/l = portable/laboratory equipment; SEM = scanning electron microscope; XRF = x-ray fluorescence. loss of engine 3. See Fig. 3 for more details on the failure and loss of engine 3[8,9]. The failure sequence as described in Fig. 3 is designated “most probable” because the inboard fuse pin was not recovered, but the complete failed lug assembly was. Note: The detachment of engine 3 resulted in its collision with engine 4, which also detached, as shown in Fig. 2. The outboard mid-spar fuse pin was noninvasively examined by optical and scanning electron microscope (SEM) fractography, which revealed multiple fatigue cracks on the outboard fracture surface that nucleated from coarse machining grooves in the thin-walled sections. Fatigue striations indicated which also caused considerable surface corrosion[1,2]. The crack arrests most probably occurred well before excavation and do not pose a continuing risk for the cup, which has been well-cleaned, transparently coated, and placed in a display cabinet with a normal air environment. NONINVASIVE BOEING 747 ACCIDENT On October 4, 1992, a Boeing 747-200 Cargo aircraft took off from Schiphol Airport. Within eight minutes, the starboard engines separated and fell at low altitude into a lake. Flight control was lost while trying to return for an emergency landing, and 16 minutes after take-off the aircraft crashed into the junction of two apartment blocks in an Amsterdam suburb and was destroyed by the impact. There were 47 fatalities, including the three aircrew and one passenger[8]. A large-scale investigation followed, involving more than 50 personnel from the National Aerospace Laboratory (NLR), Delft University of Technology, as well as experts from the Netherlands Department of Civil Aviation, and the OEM (Boeing). Figure 2 shows (a) the extent of the in-flight damage, in particular the loss of engines 3 and 4; and (b) an inset macrofractograph of one of the two fuse pins from which the accident began by
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