连续冷却搅拌A2017半固态合金流变行为研究

采用回转式熔体物性综合测试仪测定了A2017合金半固态浆料在连续冷却搅拌条件下的表观黏度变化,对其组织变化进行分析,研究了连续冷却搅拌条件下A2017合金半固态浆料的流变行为.实验结果表明,连续冷却搅拌条件下,A2017合金半固态浆料的表观黏度随固相率的增大而增大;在固相率一定的情况下,降低冷却速度或增大剪切速率,均导致表观黏度降低.显微组织观察表明,半固态浆料的流变行为与其微观组织结构有很强的关联,降低半固态浆料温度,浆料固相颗粒含量增加,表观黏度增大;降低冷却速度或增大剪切速率有利于半固态浆料固相颗粒形态向非枝晶形态的转变,因而半固态浆料表观黏度降低,流动性好.

Rheological behavior of the semi-solid A2017 alloy in a continuously cooling and stirring process

A rotational viscometer was adopted to measure the apparent viscosity of the semi-solid A2017 slurry in a continuously cooling and stirring process. The microstructure and the rheological behavior of the semisolid A2017 slurry were studied. The results show that the apparent viscosity of the semi-solid A2017 slurry increases with an increase in the solid fraction. It is also shown that the apparent viscosity of the semi-solid A2017 slurry with a specified solid fraction decreases with a decreasing cooling rate or increasing shearing rate. The analysis of the microstructures of the semi-solid A2017 slurry shows that there is a strong relationship between the microstructure and the apparent viscosity. Increasing the solid fraction leads to increments in the solid phase density and the apparent viscosity increases. Decreasing the cooling rate or increasing the shearing rate results in the solid phase shape becoming more globular due to stirring more sufficiently and the apparent viscosity decreases.