ABSTRACT Dendrite coherency point (DCP) is an important parameter for examining the solidification structure and castability of alloys. In this research, the DCP of AZ magnesium alloys (AZ31, AZ61 and AZ91) is measured in the range of 0.22 °Cs−1 to 8.13 °Cs−1 cooling rates using the two-thermocouple thermal analysis technique. The results show that when cooling rate increased, temperature interval of coherency (TN – TDCP) and coherency time (tDCP) are decreased; and it can postpone dendrite coherency. Also, by increasing the cooling rate, solid fraction at dendrite coherency increases initially and then decreases at higher cooling rates. To estimate the hot tearing susceptibility, Clyne and Davies’ criterion is used. Hot tearing susceptibility calculations exhibit initially reduce by increasing the cooling rate and then it increases at higher cooling rates. These results were explained based on the solidification principles.

中文翻译：

---

使用热分析评估冷却速率对 AZ 镁合金枝晶相干点和热裂敏感性的影响

摘要枝晶相干点（DCP）是检验合金凝固组织和可铸性的重要参数。在本研究中，AZ 镁合金（AZ31、AZ61 和 AZ91）的 DCP 在 0.22 °Cs-1 至 8.13 °Cs-1 冷却速率范围内使用双热电偶热分析技术进行测量。结果表明，当冷却速度增加时，相干温度区间（TN-TDCP）和相干时间（tDCP）减小；它可以推迟枝晶相干性。此外，通过增加冷却速度，枝晶相干的固体分数最初增加，然后在更高的冷却速度下减少。为了估计热撕裂敏感性，使用 Clyne 和 Davies 标准。热裂敏感性计算最初通过增加冷却速度而降低，然后在更高的冷却速度下增加。这些结果是基于凝固原理来解释的。