Eutectic Al-13%Si alloys are widely used in the automotive industry for manufacturing components, such as pistons and cylinder heads. To reduce greenhouse gas emissions and enhance the engine efficiency, their service temperature keeps increasing to 250-350 °C, leading to the deterioration of their mechanical properties and the creep resistance. In the present work, Mo was further added to Mn-containing Al-13%Si piston alloys aiming at improving the overall properties at elevated temperatures. Compared with the Mn-containing base alloy, Mo further enhanced the precipitation of dispersoids by expanding the dispersoid zone and restricting the dispersoid-free zone after the proper precipitation treatment (520 °C/12 h), resulting in a remarkable improvement in the yield strength at both room temperature and 300 °C, as well as the creep resistance at 300 °C. Furthermore, the beneficial effect of Mo addition on the improved yield strength and creep resistance was especially prominent during long-term thermal exposure (up to 1000 h at 300 °C) due to the synergistic effect of thermally stable dispersoids and the retardation of the gradual fragmentation and spheroidization of Si particles.

共晶Al-13％Si合金在汽车工业中广泛用于制造零件，例如活塞和气缸盖。为了减少温室气体排放并提高发动机效率，其使用温度不断提高至250-350°C，从而导致其机械性能和抗蠕变性下降。在当前的工作中，Mo被进一步添加到含锰的Al-13％Si活塞合金中，目的是改善高温下的整体性能。与含锰基合金相比，钼经过适当的沉淀处理（520°C / 12 h）后，通过扩展弥散区和限制无弥散区，进一步增强了弥散相的析出，从而显着提高了收率。在室温和300°C下的强度，以及在300°C下的抗蠕变性。此外，由于热稳定的弥散体的协同作用和缓蚀剂的缓和作用，在长期热暴露（在300°C时长达1000小时）中，添加Mo对改善屈服强度和抗蠕变性的有益作用尤为突出。硅颗粒的碎裂和球化。