外场作用下ZL201合金近液相线铸造与触变成形

Near-Liquidus Electromagnetic Casting of ZL201 Alloy and Thixoforming

采用电子显微镜、图像分析仪、维氏硬度计及电子拉伸机,研究了ZL201合金近液相线电磁铸造(NLEMC)的铸态显微组织,进行了触变成形实验,测试了成形件的力学性能.结果表明,NLEMC半固态合金坯料的组织为细小、均匀的等轴晶组织,其晶粒平均等积圆直径为68.8μm;触变成形件的维氏硬度及抗拉强度分别为116.2 HV和308 MPa,均优于电磁铸造和近液相线铸造的合金组织与触变成形件的性能;讨论了NLEMC晶粒细化的机理.

The as-cast microstructure of ZL201 alloy prepared by near-liquidus electromagnenc casting（NLEMC） was studied by means of electron microscope and image analyzer, and the mechanical properties of the alloy parts thixoformed were given through tests. The results showed that the semi-solid ZL201 alloy ingot prepared by NLEMC shows fine and homogeneous equiaxed grain structure and its average-equivalent-circle grain diameter is 48.8 prn, with the hardness of thixoformed parts 116.2 HV and tensile strength 308 MPa. All these indicated that both the ascast microstructure of ZL201 alloy and mechanical properties of its thixoformed parts prepared by NLEMC process are superior to those of the alloy prepared by either electromagnetic casting or near-liquidus casting. The mechanism of grain refinement of as-cast ZL201 alloy prepared by NLEMC was discussed.