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文章研究了用同轴双筒流变仪测定在 Couette 剪切流动中Sn-15％Pb 合金部分凝固时的流交性质。结果表明:当固相分数接近极限固相分数时,半固态浆液具有宾汉流体的流变学特征:宾汉屈服现象和剪切应力与切变速率曲线线性化。这是由于固相颗粒形成了不连续网。而当浆液中固相分数较低时,它的流变性更象假塑性流体。研究发现:在一定的剪切条件下,固相颗粒不是彼此分离的,而是存在聚集。在等温剪切流动中固相颗粒群的形成与崩溃,对部分凝固合金的流变性质有重要影响。
In this paper, the coaxial buret rheometer was used to determine the fluidity of Sn-15% Pb alloy in the Couette shear flow. The results show that the semi-solid slurry has the characteristics of Bingham fluid rheology when the solid fraction reaches the limit solid fraction: the Bingham yield phenomenon and the linearization of shear stress and shear rate curve. This is because the solid particles form a discontinuous network. When the solid fraction in the slurry is low, its rheology is more like a pseudoplastic fluid. The study found that: under certain shear conditions, the solid particles are not separated from each other, but the presence of aggregation. The formation and collapse of solid particles in isothermal shear flow have an important effect on the rheological properties of partially solidified alloys.