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Abstract: The mechanical properties of cast aluminum alloys (ADC12: Alph name="sbnd" />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 {111} and . 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 and secondary dendrite arm spacing . 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. [Copyright &y& Elsevier]

In order to examine the micro-mechanism behind the thixotropic behavior of semi-solid alloys, microstructural effects on the compression deformation of semi-solid 7075 aluminum alloy prepared by recrystallization and partial melting (RAP) method were investigated. The fibrous and deformed microstructure of as-extruded 7075 aluminum alloy can transform into elongated and globular grains via reheating to semi-solid states, and exhibiting dominated {100}<001> recrystallization texture and preferred crystal growth in extrusion direction. The anisotropic microstructure of semi-solid alloys depends on the remelting temperatures to a great degree. Correspondingly, the initial peak stress of compression stress-strain curves also demonstrated as anisotropic behavior. It was analyzed that the crystallographic texture caused orientation dependent Young's modulus and a corresponding elastic response, and the disagglometation of the saturated solid skeleton led to an increase of viscoplastic stress, which relates to the amount of bonds between solid grains. [ABSTRACT FROM AUTHOR]