Investigation of the Effects of Heat Treatment Temperature an‎d Duration on the Microstructure an‎d Corrosion Properties of Brazed Cu-Be Alloy Joint

9/7/2026 12:00:00 AM

Copper–beryllium alloys have attracted increasing attention in various industries, particularly in electronics an‎d aerospace, due to their combination of desirable properties such as high electrical an‎d thermal conductivity an‎d good corrosion resistance. The aim of this study is to investigate the effects of different aging conditions on the microstructure, corrosion resistance, an‎d hardness of hard-brazed copper–beryllium alloy, in order to determine the optimal processing conditions. The samples were first subjected to a hard-brazing process at 780 °C for 20 minutes (B), followed by annealing at 790 °C for 2 hours (S). Subsequently, three separate specimens were aged at 330 °C for 15 (H1), 120 (H2), an‎d 300 (H3) minutes, respectively. Microstructural analysis of the brazed region an‎d base metal was conducted using scanning electron microscopy (SEM) an‎d optical microscopy (OM). In addition, Vickers microhardness testing was used to eva‎luate the hardness of the joint an‎d surrounding base material. Among the samples, specimen H2 exhibited the highest hardness of 450 HV. To assess the corrosion resistance, electrochemical tests including potentiodynamic polarization (PDP) an‎d electrochemical impedance spectroscopy (EIS) were performed. The results demonstrated that post-brazing heat treatment is essential for optimizing both mechanical an‎d corrosion properties. Specifically, specimen H1 (under-aged) showed the highest corrosion resistance with a polarization resistance of 686 Ω·cm² an‎d charge transfer resistance of 176 Ω, followed by specimen S (annealed), which exhibited a polarization resistance of 620 Ω·cm² an‎d a charge transfer resistance of 223 Ω. In contrast, specimen H3 (over-aged) showed the poorest corrosion performance with a polarization resistance of only 152 Ω·cm² an‎d a charge transfer resistance of 97 Ω. These findings highlight the detrimental impact of over-aging on both corrosion resistance an‎d hardness in copper–beryllium alloys. The choice of the optimal specimen depends on the intended application of the alloy. If corrosion resistance is the sole priority, specimens S an‎d H1 are recommended. If the main goal is to achieve high hardness while maintaining acceptable corrosion resistance, specimen H2 is the best choice. However, if both high corrosion resistance an‎d adequate hardness are required simultaneously, specimen H1 offers the most balanced performance.

لحيم‌كاري سخت , آلياژ مس- بريليم , پيرسازي , پلاريزاسيون , امپدانس

Brazing , Copper–beryllium alloy , Aging , Polarization , Impedance

Reza Sepehri

Dr. Mansour Soltanieh