Core Viewpoint - 4J34 precision alloy is positioned as a typical representative of aluminum-based high-strength materials under the national military standard system, catering to the demand for high-performance precision components in various fields such as aviation, guidance control, and precision instruments [1][3]. Material Composition and Properties - The chemical composition of 4J34 precision alloy includes Al balance, Mg 1.5–2.8%, Si 0.4–1.2%, Li 1.0–2.0%, Cu 0–1.0%, Zn 0–0.5%, and Fe <0.15% [3]. - The density of 4J34 is approximately 2.60–2.70 g/cm³, which is slightly lower than traditional aluminum alloys, aiding in weight optimization [3]. - The tensile strength (Rm, T6 state) ranges from 560–640 MPa, while the yield strength (Rp0.2) is between 520–600 MPa, providing robust yield response [3]. - The elongation rate is between 6–12%, indicating controllable processing capabilities [3]. Processing and Treatment - The heat treatment process for T6 state requires solution treatment at 500–540°C, followed by aging at 160–190°C for 8–48 hours, with adjustments based on production line equipment and aluminum batch [3][4]. - Surface treatments such as anodizing and PVD/chemical plating are compatible with 4J34, enhancing corrosion resistance and reducing friction [4]. Standards and Testing - The national military standard (GJB) and national standard (GB/T) provide specific requirements for material composition, heat treatment, and inspection procedures, ensuring traceability and consistency between civilian and military products [4]. - ASTM E8/E8M is referenced for tensile testing methods, providing a consistent benchmark for stress-strain curves and fracture analysis across manufacturers [4]. Market Dynamics and Pricing - The LME aluminum price typically ranges from $2,500 to $2,700 per ton, influencing the production cost of 4J34 [4]. - The Shanghai Nonferrous Metals Network's spot quotes for aluminum usually fluctuate between RMB 100,000 and 220,000 per ton, with final product prices affected by processing losses, surface treatment, and aging processes [4]. Common Misconceptions - There is a tendency to overlook the balance between strength, fatigue, corrosion resistance, and processability when evaluating 4J34 precision alloy [4]. - The national and American standards should not be viewed as interchangeable; differences in testing methods, tolerances, and inspection frequencies necessitate establishing equivalence and conversion relationships to avoid design discrepancies [4]. - Pricing should not be the sole determining factor, as lower prices may conceal hidden costs related to processing difficulty, post-treatment costs, supply stability, and batch consistency, especially in long-term military applications [4].