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Nickel-copper alloys are commonly used in highly corrosive conditions where strength is required. Typical applications are in the marine sector, petrochemical industry, or energy facilities such as chemical tubes, pumps, heat exchangers and superheated steam systems. This paper compares the microstructure and mechanical properties of a cast alloy with a 3D printed alloy processed via a laser powder bed fusion (LPBF) technique. Small cylindrical specimens were used for tensile tests at room temperature (RT) and elevated temperatures up to 750 °C in air. The tensile stress-strain response was determined for both types of materials. At RT, LPBF material has a higher yield strength and ultimate tensile strength than a cast alloy. At elevated temperatures, the strength of both variants is comparable. However, the fracture elongation of the LPBF material is significantly lower over the entire range of investigated temperatures. Fracture surfaces and polished sections parallel to the specimen axis were investigated to compare the microstructure and damage mechanisms of the nickel-coper alloy 400 prepared by conventional casting and via LPBF.

Polycrystalline cast nickel-based superalloy IN738LC is employed for critical parts of gas turbine components in the power industry, aircraft engines, and the marine sector. These components undergo severe degradation by low cycle fatigue caused by thermal gradients, particularly during start-up and shut-down periods. The present work reports the cyclic deformation behaviour and fatigue damage of IN738LC during high-temperature isothermal fatigue. Cylindrical specimens were cyclically deformed under strain control with constant total strain amplitude in symmetrical cycling at 800 °C and 950 °C in air. The microstructure is typical of coarse dendritic grains with carbides, eutectic, and shrinkage pores. SEM imaging revealed a γ matrix with coherent L12 γ′ precipitates with bimodal morphology. Cyclic hardening/softening curves, cyclic stress-strain response, and fatigue life diagrams were determined. An increase in testing temperature is associated with a significant decrease in stress amplitude and an increase in plastic strain amplitude. The fatigue life gradually decreases with increasing temperature. The fracture surfaces and polished sections parallel to the specimen axis were examined to study damage mechanisms in cyclic loading at high temperatures.