Effect of Simulated Brazing Cycle on the Microstructure and Mechanical Properties of Cu-Cr-Zr-Ti Alloy

Abstract

Cu-Cr-Zr-Ti alloys are widely used for fabrication of thrust chamber in liquid rocket engines, because of their high thermal conductivity and adequate strength. The alloy should be used in peak-aged condition to achieve the best combination of strength and conductivity. However, realization of final component involves forming and brazing operations which limit the usage of the alloy in peak aged condition. Therefore, an attempt has been made to study the effect of the simulated brazing treatment on the microstructure and mechanical properties using optical microscopy, electron microscopy, mechanical testing and hardness measurement. The high temperature brazing treatments resulted in tremendous grain growth. The measured hardness is observed to be in line with the grain size of the specimens. The hardness and tensile strength decreased in samples subjected to simulated brazing cycle, implying requirement for a post braze treatment. After the post brazing treatment the optimum mechanical properties have been achieved at room temperature. Low ductility was observed at 600°C in the samples subjected to simulated brazing cycle.