Mechanical properties of Al-Si₁₃-Ni_1.4-Mg_1.4-Cu₁ alloys produced by the Ohno continuous casting process

Examination of the mechanical properties of cast aluminum alloys (AC8A: Al-Si₁₃-Ni_1.4-Mg_1.4-Cu₁), created by the Ohno continuous casting (OCC) process, was conducted. The material strength and ductility of the OCC samples are twice as high as the same aluminum alloy produced by conventional gravity casting. The increase of material strength of the OCC sample is attributed to (i) tiny spherical α-Al grains, (ii) fewer cast defects and (iii) solid-solution strengthening by silicon. The high material ductility of the OCC sample is related to the regularly oriented crystal structure, where the crystal direction (111) in the cast sample is perpendicular to the casting direction, and (110) and (100) directions can be detected in the longitudinal direction of the sample. The yield stress of the OCC sample can be estimated by two different parameters: solid-solution strengthening, k√c, and grain size, ky/√d (Hall-Petch relation).