The aim of this study was to determine the correlation between the size and the distribution of microstructural constituents and their cooling rate, as well as the correlation between the mechanical properties and the cooling rate of AlSi9Cu3 aluminum alloy when cast in high-pressure die casting (HPDC) conditions. In other words, the ultimate goal of the research was to determine the mechanical properties for a casting at different cooling rates. Castings with different wall thicknesses were chosen, and different cooling rates were assumed for each one. Castings from industrial technological practice were systematically chosen, and probes were extracted from those castings for the characterization of their mechanical properties. Special non-standard cylinders were created on which compressive tests were carried out. The uniqueness of this research lies in the fact that the diameters of the designed cylinders were in direct correlation to the actual wall thickness of the castings. This is important because the solidification of metal in the die cavity is complex, in that the cooling rates are higher on the surface of the casting than in the center. Local in-casting cooling rates were determined using numerical simulations. It was discovered that with increasing cooling rates from 60 K/s to 125 K/s the values for strength at 5% deformation increased on average from 261 MPa to 335 MPa.

中文翻译：

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冷却速度对AlSi9Cu3组织和力学性能的影响

这项研究的目的是确定在高压压铸中铸造的AlSi9Cu3铝合金的微观组织成分的尺寸和分布及其冷却速率之间的相关性，以及力学性能与冷却速率之间的相关性（ HPDC）条件。换句话说，研究的最终目标是确定不同冷却速率下铸件的机械性能。选择具有不同壁厚的铸件，并假设每种铸件具有不同的冷却速率。系统地选择了来自工业技术实践的铸件，并从这些铸件中提取了探针以表征其机械性能。创建了特殊的非标准气缸，并在其上进行了压缩测试。这项研究的独特之处在于，设计圆柱体的直径与铸件的实际壁厚直接相关。这很重要，因为模腔中金属的固化很复杂，因为铸件表面的冷却速率高于中心的冷却速率。使用数值模拟确定局部铸件冷却速率。发现随着冷却速率从60 K / s增加到125 K / s，5％变形时的强度值平均从261 MPa增加到335 MPa。这是因为铸件表面的冷却速率高于中心的冷却速率。使用数值模拟确定局部铸件冷却速率。发现随着冷却速率从60 K / s增加到125 K / s，5％变形时的强度值平均从261 MPa增加到335 MPa。这是因为铸件表面的冷却速率高于中心的冷却速率。使用数值模拟确定局部铸件冷却速率。已经发现，随着冷却速率从60 K / s增加到125 K / s，5％变形时的强度值平均从261 MPa增加到335 MPa。