Copper-based alloys: influence of alloying content on their thermo-mechanical properties and applications

Abstract

Copper is a metal widely used in engineering and in various industrial applications, due to its excellent properties of high electrical and thermal conductivity, good corrosion resistance, good mechanical properties, and ease of processing. In addition to its good mechanical and physical properties, copper has antimicrobial properties against bacteria, viruses and fungi, and promising biological performance. For certain specific applications it is necessary to add alloying elements that give the material particular properties. The most common and commercially available copper-based alloy families are brasses, bronzes, silicon bronzes, aluminum bronzes, and beryllium bronzes. Age-hardenable Cu-2Be alloy can exhibit high strength and hardness after the formation of γ’ metastable nanoprecipitates by aging treatments. After 45 minutes at 400°C, the material can reach a hardness of 354 HV and an elastic modulus of almost 120 GPa. Aluminum bronze Cu-9Al-4Fe is an alloy that contains α, β’ and intermetallic κ phases. Aging treatments at 400°C produce a slight increase in hardness and elastic modulus due to changes in the fraction of phases present. The selection of the required material and the heat treatments to be performed must depend largely on the specific application and the demands placed on the material. On the other hand, for the study of these materials, different aspects must be considered, such as the size of the phases present and the detection capacity of the constituent elements. In particular, the study of aged Cu-2Be alloys requires careful studies, due to the nanometric size of the precipitates and the low atomic number of Be.