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technical paper
Process Development for Laser Powder Bed Fusion of Grcop-42 Using a 515 NM Laser Source
keywords:
grcop-42
green laser
copper alloys
laser powder bed fusion
additive manufacturing
Copper is widely used in high heat flux and electrical applications due to the excellent electrical and thermal conductivity properties. Alloying elements such as chromium or nickel are added to strengthen the material especially for higher temperatures. Cu4Cr2Nb or GRCop-42 is a dispersion strengthened alloy developed by NASA for high temperature applications with high thermal and mechanical loads such as rocket engines. Additive manufacturing enables applications with complex functionalised geometries and is especially promising in the aerospace industry. In this contribution, a parametric study was carried out for GRCop-42 and the AM process laser powder bed fusion using a green laser source for two layer thicknesses of 30 and 60 μm. The density, electrical conductivity, macro hardness, microstructure and static mechanical properties were analysed. Various heat treatments in the temperature range of 400 °C and 1000 °C and time range of 30 min to 4 h were tested to increase electrical conductivity and hardness. For both layer thicknesses, dense parameter sets could be obtained with resulting relative densities above 99.8 %. The hardness and electrical conductivity could be tailored depending on the heat treatment in the range of 103 to 219 HV2 and 24 to 88 % International Annealed Copper standard. The highest ultimate tensile strength obtained was 493 MPa. An annealing temperature of 700 °C for 30 min has shown the best combination of room temperature properties such as electrical conductivity of 83.76 %IACS, UTS of 481 MPa, elongation at break at 24 % and hardness of 125 HV2.