Copper-beryllium alloys combine strength with useful electrical and thermal properties, but a property value is meaningful only when the alloy, product form and condition are known. This reference is limited to Materion Alloy 25, UNS C17200, in rod and bar. The manufacturer identifies the listed elastic and physical properties for precipitation age-hardened material and gives separate temperature conditions for thermal expansion and conductivity.

Beryllium copper wrought alloy properties

Scope of the values

Alloy 25 is a precipitation-hardening copper-beryllium grade. The values here are not a combined catalog for every copper-beryllium product. Strip, plate, tube, wire, rod and bar can have different processing routes and product specifications. Even when the alloy number is the same, strength and other properties can depend on temper, thickness, orientation and heat treatment. The table therefore names the product form and condition instead of implying one universal C17200 value set.

Materion reports a 131 GPa elastic modulus and an electrical conductivity range of 25–30% IACS for the listed age-hardened rod/bar condition. The corresponding resistivity range is 5.8–6.9 µΩ·cm. Conductivity and resistivity describe the same electrical behavior in different forms, but they are listed as the manufacturer reports them and should not be independently mixed or rounded into a new specification. The datasheet lists density as 8.36 g/cm³ after heat treatment.

Temperature-dependent properties

The reported mean thermal expansion coefficient is 17.5 µm/(m·°C) over the stated 20–200 °C interval. It is not a promise that the same coefficient applies across every temperature span or thermal history. Thermal conductivity is listed as 105 W/(m·K) at 25 °C. If a design depends on behavior at another temperature, use a temperature-specific source or request data for the actual condition rather than carrying the room-temperature value forward without checking.

Using the data in a design

For a first comparison, the table can help identify the scale of the alloy’s stiffness, electrical conduction, density and heat transfer. It does not provide a certified yield strength, ultimate tensile strength, fatigue limit or allowable stress. Those values require a product-form-specific technical sheet and design basis. Do not infer tensile performance from the alloy family, conductivity, density or elastic modulus.

When specifying material, call out UNS C17200 together with product form, temper, dimensions, governing specification and certification requirements. Check the supplier’s current mill data and lot certificate for the actual material. If the application includes elevated temperature, cyclic loading, contact current or critical structural loads, use property values and design allowables appropriate to that service and consult the alloy supplier or responsible materials engineer.

Handling and manufacturing note

Beryllium-containing material requires appropriate workplace controls, especially during operations that create dust or fumes. Follow the supplier’s safety data sheet and applicable occupational requirements for cutting, grinding, welding, heat treatment and waste handling. This property table is not a safety procedure, purchasing specification or approval for a particular design.

The dataset intentionally keeps this narrow: it reports selected properties from the manufacturer’s Alloy 25 rod-and-bar page and preserves the stated heat-treatment or temperature condition. It does not fill gaps with handbook OCR or values from another alloy, temper or product form.

Temper notation is part of the material identity. The same C17200 chemistry can be supplied in solution-treated, age-hardened or other specified conditions, and the resulting properties need not match. Keep the certificate and product data with the component record, and ask the supplier to resolve any discrepancy between the drawing temper, certificate and catalog sheet before machining or assembly.

Do not use the listed elastic modulus to estimate yield strength, and do not treat the room-temperature electrical or thermal figures as guaranteed values for an unspecified test method. The datasheet condition and listed temperature span are boundaries on the data, not optional notes. If your load case needs a value that is not in this table, obtain it for the exact alloy form and condition.