Microstructure and high-temperature mechanical properties of new-type heat-resisting aluminum alloy Al6.5Cu2Ni0.5Zr0.3Ti0.25V under the T7 condition

Abstract

Making use of the low-pressure sand mold casting preparation Al6.5Cu2Ni0.5Zr0.3Ti0.25V alloy. After T7 heat treatment, microstructure observation shows that the average grain size of the Al matrix is 150 μm, and the second phase is θ'-Al2Cu, Al7Cu4Ni, Al3M (M = Ti, Zr, V). The tensile strength is 127.5 MPa, the yield strength is 108Mpa, and the elongation is 16.11 %. The θ'-Al2Cu phase in the grain, a small amount of Al3M (M = Ti, Zr, V) thermal stable phase, and the Al7Cu4Ni phase at the grain boundary make the alloy exhibit excellent high-temperature mechanical properties at 350℃.