Arc additive remanufacturing of a new type of Al–Cu–Ni aviation case: microstructure and high-temperature properties under T6 heat treatment

A new Al–Cu–Ni alloy was repaired by arc additive remanufacturing and T6 heat treatment. The results show that the grain size in the upper part of the weld is slightly larger than that in the lower part, and the whole distribution is uniform without delamination. The orientation of grains in the weld is disordered, and most of them are stable crystal structures with a large angle. The average tensile strength at 300°C is 148.3 MPa, the yield strength is 106.6 MPa and the elongation is 10.5%. δ-Al3CuNi and γ-Al7Cu4Ni increase the strength of grain boundary, and the strength of θ″ and θ′ are dispersed from the α-Al matrix during aging, which are the main reasons for obtaining high-temperature properties.