Brass (Cu70/Zn30) is a copper-zinc alloy valued for its distinctive balance of strength, ductility, corrosion resistance, and attractive golden color. This particular composition, known as cartridge brass or alpha brass, combines the excellent workability of copper with the hardness and wear resistance imparted by zinc, making it one of the most versatile and widely used copper alloys in engineering and decorative applications.
Material Overview
The Cu70/Zn30 alloy belongs to the alpha brass family, characterized by a single-phase face-centered cubic (FCC) structure that provides high ductility and excellent cold-forming behavior. Its typical density is about 8.5 g/cm3, with tensile strengths ranging from 300 to 500 MPa depending on processing and tempering. Electrical conductivity remains around 28–30% IACS, while thermal conductivity averages 120 W·m−1·K−1. Studies by Shahriyari et al. (2022) demonstrated that multi-directional forging of Cu-30Zn alloys can enhance hardness by over 200% through grain refinement without significantly reducing conductivity. Furthermore, Balanović et al. (2025) found that thermal and electrical conductivities of CuZn30 alloys decrease slightly with increasing zinc concentration, reflecting the strong electron scattering effect of zinc in the copper matrix. These properties make Cu70/Zn30 an ideal balance between mechanical robustness and conductivity.
Applications and Advantages
Brass Cu70/Zn30 is extensively used in heat exchangers, musical instruments, ammunition casings, valves, and decorative fittings. Its high corrosion resistance, especially in mildly acidic and saline environments, makes it suitable for marine and architectural uses. The alloy’s good machinability and ability to form intricate shapes lend themselves to fine engineering components such as screws, fasteners, and tubing. Liu et al. (2022) reported that increasing copper content in brass improves stress corrosion resistance and electrical conductivity, making Cu70/Zn30 a favorable compromise for electrical connectors and transformer terminals. Recent alloy design advances (Berndorf et al., 2024) have also yielded dezincification-resistant variants of CuZn30 alloys, ensuring longer service life and stability under humid or chemically aggressive conditions.
Goodfellow Availability
Goodfellow offers Brass (Cu70/Zn30) in a variety of customizable forms including sheets, spheres, and rods, available in high-purity research and industrial grades. The material is suitable for experimental metallurgy, conductivity testing, and design applications requiring aesthetic and mechanical precision.
Explore Brass Cu70/Zn30 – Sphere – Material Information and other advanced materials in Goodfellow’s online catalogue: Goodfellow product finder.
References
- Shahriyari, F., Shaeri, M. H., Dashti, A., Zarei, Z., Talafi Noghani, M., Cho, J. H., & Djavanroodi, F. (2022). Evolution of mechanical properties, microstructure and texture of brass alloys processed by multi-directional forging. Materials Science and Engineering A, 833, 142149. https://doi.org/10.1016/J.MSEA.2021.142149
- Balanović, L., Nikolajević, A., Manasijević, D., Marković, I., Gorgijevski, M., Stamenković, U., & Božinović, K. (2025). Investigation of thermal and electrical properties of copper alloys. MMESEE, 93. https://doi.org/10.30544/mmesee93
- Liu, W., Yi, Y., Cao, X., Xi, C., Wang, Z., Xie, Y., & Feng, C. (2022). Research on the performance of brass alloy main transformer terminal. Journal of Physics: Conference Series, 2174(1), 012054. https://doi.org/10.1088/1742-6596/2174/1/012054
- Berndorf, S., Markelov, A. I., Guk, S., Mandel, M., Krüger, L., & Prahl, U. (2024). Development of a dezincification-free alloy system for the manufacturing of brass instruments. Superalloys, 14(7), 800. https://doi.org/10.3390/met14070800