In the last decades, new machine systems have enabled the manufacturing of dense component parts of high reflective metals like copper by using green laser sources and the laser powers up to 1 kW, respectively. One of the most commonly used low-alloyed copper alloy is the system CuCr1Zr. The key feature of CuCr1Zr is a high strength and a sufficient conductivity at the same time. The high strength is based on the formation of nano-scaled intermetallic phases during precipitation hardening. At CuCrZr, predominantly chromium precipitates and intermetallic phases like Cu_xZr_y are formed [1]. Here, additively manufactured CuCrZr offer a higher strength in comparison to conventional treated CuCrZr. The reason for the higher strength is related to the high cooling rates at LPBF. Using a laser as a heat source, a higher amount of alloying element can be solved into the copper matrix. Consequently, more intermediate phases are formed during the precipitation hardening. In addition, ZrO₂ is formed, leading to a further improvement of the material properties.

Within the scope of the study, a systematically analysis of additively manufactured CuCrZr by changing the chromium concentration from 0 wt.-% to 2 wt.-% is considered to increase the ratio of strength and electrical conductivity of CuCrZr. Afterwards, the resulting strength was tested, respectively, via tensile testing and is verified by micro- and nanostructural analysis. Therefore, the samples were then metallographically prepared and characterized with the help of analytical scanning electron microscopy in combination with EDX, EBSD and FIB with regard to pore formation, anisotropy and precipitation formation. The analysis is accompanied by TEM investigations of the formed intermetallic phases.

References
[1] X. Tang, et al., Materials & Design, 2022, 224, p. 111419