{"L1_core": {"domain": "material", "category": "metal", "subcategory": "non-ferrous", "atomic_number": 13, "element_symbol": "Al"}, "L5_metadata": {"updated": "2026-01-04", "version": "1.0"}, "L3_standards": {"en": ["EN 573"], "iso": ["ISO 209"], "astm": ["ASTM B221"]}, "L2_properties": {"physical": {"density_g_cm3": 2.70, "melting_point_c": 660, "thermal_conductivity_w_mk": 237}, "mechanical": {"elastic_modulus_gpa": 70, "tensile_strength_mpa": [90, 700]}, "characteristics": ["lightweight", "corrosion-resistant", "recyclable", "ductile"]}, "L4_applications": ["aerospace", "construction", "packaging", "electronics"]}