C17200 beryllium copper alloy: The industrial benchmark of high-strength elastic materials

The C17200 beryllium copper, with a perfect balance of 1400 MPa tensile strength and 22% conductivity, has become an indispensable material in high-end fields such as aerospace and electronic communications. The usage for a single Boeing 787 aircraft can reach as high as 150 kilograms.

C17200 beryllium copper (UNSW number C17200) is the most widely used precipitation-hardening copper alloy in the ASTM standards. As the flagship model of the C17000 series, its 1.80-2.00% beryllium content and 0.20-0.40% cobalt/nickel addition have achieved the performance peak in the copper alloy field. After aging treatment, the tensile strength can reach 1400 MPa (an increase of nearly 10 times compared to pure copper), while maintaining 22% IACS conductivity and 3% elongation. This unique combination of properties enables it to continuously dominate in critical components with strict requirements.

C17200 beryllium copper (Beryllium Copper Alloy, AISI C17200) is a precipitation-hardening alloy with copper as the base material, containing 1.90 - 2.15% beryllium (Be), and trace amounts of cobalt (Co) and nickel (Ni). After solution treatment and aging treatment, it can simultaneously possess extremely high strength, excellent elastic limit and fatigue resistance, as well as good electrical conductivity, thermal conductivity, corrosion resistance and wear resistance. It is hailed as the "industrial wonder steel" and is widely used in mold manufacturing, mechanical engineering, electronic and electrical fields.

Material properties and strengthening mechanisms

Core component parameters and chemical composition and strengthening mechanism.

Beryllium (Be) 1.90 - 2.15%

The precipitation of Ni₃Be (γ' phase) and CuBe₂ and other strengthening phases significantly enhances the tensile strength and yield limit of the alloy, while maintaining excellent elastic limit and fatigue life.

Cobalt (Co) 0.35 - 0.65%, Nickel (Ni) 0.20 - 0.25%

Micro-diffusion strengthening, optimizing the distribution of precipitated phases and the microstructure of the matrix, improving corrosion resistance and stability in high-pressure environments.

Copper (Cu) content

Provides high thermal conductivity (≈ 105 W/m·K) and high electrical conductivity (≈ 18% IACS), ensuring the requirements for thermal management and electrical conduction.

Minor impurities (Si, Fe, Al < 0.15%).

Physical performance characteristics

Density: 8.25 g/cm³ (at 20℃)

Elastic modulus: 131 GPa (in aged state)

Electrical conductivity: 18 - 22% IACS (in the aged state)

Thermal conductivity: 115 W/(m·K)

Tensile strength: 1140 - 1400 MPa (depending on processing condition)

Yield strength: 1000 - 1200 MPa

Strain rate: 3 - 12% (present tense)

Fatigue limit: 380 MPa (10⁸ cycles, R = -1)

Microscopic strengthening mechanism

By carrying out 790-810℃ solid solution treatment followed by 315-345℃ for 2-3 hours of aging, a γ'-CuBe nano-crystalline precipitate phase (with a size of 5-15 nm) is formed. This phase forms a semi-identical interface with the matrix, resulting in a lattice mismatch degree of 4.8%, which triggers a strong coherent strain field strengthening effect. During the aging process, the hardness can increase from HRB65 (solid solution state) to HRC44 (peak aging), and the nano-indentation hardness reaches 6.5 GPa.

Industrial applications and performance advantages

Electronic communication field

High-speed connectors: Elastomeric contacts made from 0.2mm thick strip material, the contact force stability (ΔF/F₀ < 5%) is 10 times that of phosphor bronze.

RF coaxial connectors: Utilizing its 58GPa stiffness and low insertion loss characteristics (<0.05dB@40GHz).

Chip test sockets: 0.1mm probes can withstand 100,000 impact tests of 5N.

High-end equipment field

Aircraft engine sealing ring: Maintains a strength of 500 MPa even during short-term operation at 650℃.

Satellite solar wing hinge: Fatigue life exceeds 1×10⁷ times (equivalent to 15 years of orbital operation).

Deep well drilling tools: Anti-sulfuric acid stress corrosion performance is 20 times that of ordinary copper alloys.

Precision manufacturing field

Optical mirror mold: The thermal conductivity is 7 times that of mold steel, and the cooling efficiency is increased by 400%.

Precision gears: Gear传动 error for a gear with a module of 0.1 is less than 1 minute's angle.

Medical catheter and guide wire： The transmission efficiency of the pushing force for a wire with a diameter of 0.3mm is 95%.

Key process control:

Heat treatment: Hot rolling at 790-810℃, final rolling temperature ≥ 650℃ (to prevent beryllium segregation).

Solution treatment: Water quenching with cooling rate > 120℃/s (to inhibit over-aging).

Tempering control: Three-stage tempering (260℃ × 1h + 315℃ × 1h + 345℃ × 1h) can achieve the best comprehensive performance.

Key points of precision processing

Cutting parameters: Linear speed of PCD tool 80 - 150 m/min, cutting depth ≤ 0.1 mm.

Grinding specifications: Diamond grinding wheel grit size 600#, coolant conductivity < 5 μS/cm.

Electrical discharge machining: Discharge energy < 50 μJ, surface white layer thickness < 3 μm.

Surface treatment technology

Chemical nickel plating: Pre-plating with impact current density of 50A/dm² (lasting for 0.5s), with coating adhesion strength ≥ 80MPa.

Laser polishing: Treatment with femtosecond laser (pulse width < 500fs), surface roughness Ra < 0.03μm.

Ion plating: CrN coating thickness of 2-5μm, friction coefficient reduced to 0.15.

Standard supply form

Ultra-thin strip: Thickness 0.02 - 0.5mm (tolerance ± 0.5 μm).

Precision wire: Diameter 0.02 - 10mm (relaxation resistance Δσ/σ₀ < 0.5%/1000h).

Special-shaped parts: Complex cross-section parts with the minimum inner angle of R0.05mm.

Conclusion

C17200 beryllium copper, with its four core advantages of "high strength + high elasticity + high thermal conductivity + high electrical conductivity", leads the new era of multi-functional application of industrial alloy materials. From injection molds and hot runner nozzles, to high-speed spindle bearings and precision electronic connectors, C17200 can enhance the value of products with extraordinary performance and reliability, making it the best choice for you to achieve efficient production and long-term reliability.