Development of high strength Al alloys produced by newly proposed high speed continuous casting

本研究开发了高速热型连铸工艺。通过这种铸造工艺，生产出高质量的铸造样品，其表现出优异的机械性能（高强度和高延展性），这些机械性能是通过常规重力铸造生产的相同合金的机械性能的约两倍。采用不同组织特征的试样（SDAS和共晶组织），研究了铸造速度对力学性能的影响。SDAS与拉伸性能之间存在线性相关关系。然而，当共晶组织的直径超过0.003mm时，当UTS和延展性显著降低时，这些线性相关性被打破，特别是对于UTS与SDAS和应变与SDAS。对于大于0.003mm的共晶组织，失效由脆性共晶相主导，SDAS不再与UTS和应变强烈相关。

In this research, the high speed heated-mold continuous casting process was developed. With this casting process, high quality cast samples were produced, which exhibit excellent mechanical properties (high strength and high ductility) that are about twice as high as those for the same alloy produced by conventional gravity casting. The effects of casting speed on the mechanical properties were investigated, using the samples with different microstructural characteristics (SDAS and eutectic structures). There are linear correlations between SDAS and tensile properties. These linear correlations, however, break down, especially for UTS versus SDAS and strain versus SDAS, as the eutectic structures become more than 0.003mm in diameter, when the UTS and ductility decrease significantly. For eutectic structures larger than 0.003mm, failure is dominated by the brittle eutectic phases, for which SDAS is no longer strongly correlated with UTS and strain.