Superior strength-ductility-conductivity synergy of GRCop-42 alloy manufactured via electron beam powder bed fusion

In response to the urgent demand for high-strength and high-conductivity copper alloys in the regenerative cooling combustion chambers of rocket engines, in this study, GRCop-42 alloy was formed in one go by electron beam powder bed fusion (EB-PBF). The influence of EB-PBF linear energy density (LED) on the density-microstructure-comprehensive performance of alloy samples was systematically studied. When the LED was 408 J m −1 , almost fully dense alloy samples were obtained with a relative density of 99.54 %. Under this parameter, the sample exhibits excellent coupling of mechanical and electrical properties, with tensile strength and electrical conductivity of 300 MPa and 70 %IACS, respectively. The sample melt pool shows a gradient of fine to coarse grains, and the average grain size gradually increases with the increase of the LED. In addition, the samples formed by EB-PBF in-situ precipitated Cr 2 Nb, Cr 2 O 3 and Cr phase <10 nm in the matrix. These precipitated particles are the main reason for the excellent mechanical and electrical properties of the sample. This work has expanded the application scope of EB-PBF in the field of high-performance copper alloys and reserved technical solutions for achieving lightweight and integrated manufacturing of rocket combustion chambers.