Mechanical properties of AlSiCu alloys produced by the twin rolled continuous casting process

The mechanical properties of cast aluminum alloys (ADC12: Al. Si. Cu alloy), created by the twin rolled continuous casting (TRC) process are explored. The TRC-ADC12 exhibits an anisotropic microstructure formed by a fine dendritic microstructure of the columnar and equiaxial grains in the longitudinal direction. Deformation twinning occurs in the TRC sample for several reasons including a high strain rate, high rolling force and fine grains; lattice rotation occurs along {1. 1. 1} and 〈1 1 2̄〉. The tensile and fatigue strengths of the TRC samples are about twice those of the same aluminum alloy produced by conventional gravity casting. This increase is attributed to the fine grains and fewer casting defects for the TRC samples. The 0.2% proof stress of the TRC samples can be estimated by two different parameters, solid-solution strengthening kc and secondary dendrite arm spacing ky/d. An anisotropic microstructure of the TRC samples makes a slight difference in the mechanical properties between the longitudinal and perpendicular directions, and the tensile and fatigue strengths of the samples in the longitudinal direction are slightly higher than those in the perpendicular direction. Based upon the microstructural characteristics, further details of the mechanical and fatigue properties are discussed based on experimental and numerical data.