准共晶型ZL109合金半固态锻造成形组织演变特征与力学性能研究

Structure evolution of ZL109 alloy in the process of semi-solid forging and its mechanical properties

试验研究了ZL109合金在半固态锻造成形过程中(坯料制备,二次重熔和零件成形)的组织演变及成形零件的热处理工艺和力学性能。结果表明:在坯料制备过程中,低过热浇注使坯料微观组织中的共晶硅片细化;在二次重熔时共晶组织熔解,共晶硅片进一步细化和团块化;在半固态锻压成形流动过程中,合金微观组织间发生了摩擦、变形,使得α相球团化,共晶组织细化;半固态锻压零件在热处理过程中,共晶组织中的α相向初生α相聚集成球团状,而共晶组织中的硅颗粒聚集成团块硅相;制备合金坯料的合理低过热浇注温度为566℃,合理的半固态锻造温度为569℃;合金热处理以后伸长率从0%提高到1.42%,比一般铸造方法所得的铸件的塑性明显要高。

The characteristics of structure evolution of ZL109 alloy in three procedures, the preparation of billets, the remelting process and semi-sohd forging were investigated as well as the mechanical properties of the part. Results of the investigation show that low super-heat casting could refine the crystal. The eutectic structure fused and the crystals of silicon phase become spherical gradually in the remelting process. In semi-solid forging process, the sphericity of a phase and the refining of the silicon phase in the eutectic occur. In the process of the heat treatment of the component forged, a phase in the eutectic aggregated with the primary a phase, meanwhile the silicon pieces in the eutectic aggregated together. The elongation of the alloy of the component semi-solid forged rises to 1.42% after heat treatment from 0 obtained in the alloy cast with a common liquid casting process, which shows a dramatic increase of the plasticity Of the alloy with the semi-solid forging process.