【摘要】 利用Couette型同轴双筒流变仪检测了半固态AlSi4Mg2合金浆料的等温稳态表观粘度．结果表明:半固态AlSi4Mg2 合金浆料的稳态表观粘度随着固相分数的增加而增大,并且当固相分数达到某一临界值之后迅速增大．当固相分数较低时,半固态 AlSi4Mg2合金浆料的粘滞力主要来自液态合金的粘度,但随着固相分数的增加,固相颗粒之间以及与液相之间的碰撞和摩擦变得越来越强烈,使得合金浆料的表观粘度越来越高．半固态AlSi4Mg2合金浆料的稳态表观粘度随着剪切速率的增大而减小,并且随着剪切速率的提高,表观粘度急剧增大,所对应的临界固相分数也随着增大．当剪切速率很高时,固相颗粒的形状更加趋于球化,浆料的粘滞力下降,浆料的表观粘度就更小．半固态AlSi4Mg2合金浆料的稳态表观粘度ηa与固相分数fs和剪切速率γ之间的关系可以近似地表示为ηa=25．5exp(6．13fs)γ-1.16．更多还原

【Abstract】 The apparent viscosities of semi-solid AlSi4Mg2 alloy were investigated in the steady state. The results show that the apparent viscosity of the semi-solid slurry increases with the solid fraction increasing, but the apparent viscosity goes up sharply as the solid fraction reaches a critical value. However, when the solid fraction is increased to some extent, the apparent viscosity becomes bigger and bigger. The apparent viscosity of the semi-solid slurry declines with the shearing rate increasing, and the critical solid fraction causing the apparent viscosity to rise sharply becomes bigger if the shearing rate increases. When the shearing rate is high, the slurry is stirred more violently and the solid particles become more spherical, so the viscous resistance decreases and the apparent viscosities become lower. The effect of solid fraction fs and shearing rate γ on the apparent viscosities of semi-solid AlSi4Mg2 alloy slurry can be expressed as ηa = 25.5exp(6.13fs)γ-1.16.更多还原