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采用机械搅拌的半固态铸造技术制备Sn-52Bi合金,探索了不同固相率下剪切力和作用时间对半固态Sn-Bi合金组织和塑性的影响。结果表明,在近液相线的146℃(固相率为4%),搅拌速度为320 r/min和搅拌6 min的工艺条件下,制备出分布均匀、直径约10μm球状初生相的半固态Sn-52Bi合金,其伸长率为31.3%,与在180℃下的合金金属熔液直接水冷凝固而成的相比提高了74.8%。随着剪切力作用时间的延长和半固态合金浆料中固相率的增加,半固态浆料的初生相易发生团聚,所制备的半固态Sn-Bi合金初生相为分布不均的蔷薇形或椭圆形,合金伸长率下降。
Sn-52Bi alloy was prepared by semi-solid casting with mechanical stirring. The effects of shear stress and reaction time on microstructure and plasticity of semi-solid Sn-Bi alloy were investigated. The results showed that under the conditions of 146 ℃ (4% solid phase), stirring speed of 320 r / min and stirring for 6 min, the semisolid state of the uniformly distributed spherical primary phase with a diameter of about 10 μm The Sn-52Bi alloy had an elongation of 31.3%, an increase of 74.8% as compared with that obtained by direct solidification of the alloy metal melt at 180 ° C. With the extension of shearing force and the increase of the solid fraction in the semi-solid alloy slurry, the primary phase of the semi-solid slurry tends to agglomerate, and the semi-solid Sn-Bi alloy primary phase is the unevenly distributed rose Shape or oval, alloy elongation decreased.