Abstract Dual hardening steels achieve secondary hardening through the combined precipitation of intermetallic phases and carbides. The early stages of precipitation of a Cu-Ni-Al medium carbon alloyed dual hardening steel with a low alloying ratio of Cu/NiAl were investigated. Phase separation during continuous heating with 20 K min−1 was identified to occur in the temperature range from 360 °C to 620 °C by differential scanning calorimetry. The precipitates were characterized utilizing atom probe tomography. Different cluster search algorithms were used in order to determine the sequence of phase separation and thus identify the individual precipitation reactions. It was shown that phase separation starts with the formation of Cu (Ni, Al, Mn) clusters. At an ageing temperature of 580 °C, heterogeneous precipitation of VC-clusters at the interfaces between the Cu-precipitates and the iron matrix takes place. A phase separation of the Cu (Ni, Al, Mn) clusters into separate Cu and NiAl particles could not be observed up to an ageing temperature of 620 °C. The sequence of precipitation is thus determined to be Cu-VC-NiAl.

中文翻译：

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Cu-Ni-Al中碳合金双硬化钢中的沉淀反应

摘要 双硬化钢通过金属间相和碳化物的复合析出实现二次硬化。研究了具有低合金化比例的 Cu-Ni-Al 中碳合金双硬化钢的早期析出阶段。通过差示扫描量热法确定在 360 °C 至 620 °C 的温度范围内以 20 K min-1 连续加热期间发生相分离。使用原子探针断层扫描表征沉淀物。使用不同的聚类搜索算法来确定相分离的顺序，从而确定各个沉淀反应。结果表明，相分离始于 Cu（Ni、Al、Mn）簇的形成。在580°C的老化温度下，在铜沉淀物和铁基体之间的界面处发生 VC 团簇的异质沉淀。在 620 °C 的时效温度下，无法观察到 Cu（Ni、Al、Mn）簇的相分离成单独的 Cu 和 NiAl 颗粒。因此确定沉淀顺序为Cu-VC-NiAl。