This work aimed to investigate the martensitic transformation and precipitation of CoCrMo alloys fabricated by selective laser melting (SLM) under aging heat treatment. SLM-fabricated CoCrMo alloy was a mixture of γ-phase and ε-phase, and the content of γ-phase was about 70%. The content of ε-phase increased with the aging time. A nearly pure ε-phase was achieved by aging at 900 °C for 10 h in the SLM-fabricated part. After aging treatment for a short-time, the microhardness of the parts decreased comparing to the AS-SLM probably due to the disappearance of the honeycomb precipitates. The EDS results showed that those granular precipitates in SLM900 and SLM750 are M₂₃C₆. The content of M₂₃C₆ increased with aging time. The M₂₃C₆ precipitates and martensitic transformation enhanced the microhardness. Specimens with highest microhardness were obtained by aging at 900 °C for 10 h. This result established the relationship between the heat treatment process, microstructure and microhardness.

这项工作旨在研究在时效热处理下通过选择性激光熔化（SLM）制造的CoCrMo合金的马氏体转变和析出。SLM制造的CoCrMo合金是γ相和ε相的混合物，并且γ相的含量约为70％。ε相的含量随着时效时间的增加而增加。通过在SLM制造的零件中在900°C的温度下老化10 h，可以获得接近纯的ε相。经过短时间的时效处理后，与AS-SLM相比，零件的显微硬度降低了，这可能是由于蜂窝状沉淀物的消失所致。EDS结果表明，SLM900和SLM750中的颗粒状沉淀为M ₂₃ C ₆。M ₂₃ C ₆的含量随着老化时间的增加而增加。他们₂₃ C ₆析出物和马氏体相变增强了显微硬度。通过在900°C下老化10 h获得具有最高显微硬度的样品。该结果建立了热处理工艺，显微组织和显微硬度之间的关系。