液-固温区A356合金剪切速率阶梯变化的瞬态流变行为  

STUDY ON TRANSIENT RHEOLOGICAL BEHAVIOR OF SEMI-SOLID A356 ALLOY APPLIED WITH STEP VARIED SHEAR RATE

作　　者：唐靖林[1] 殷雅俊[1] 范钦珊[1] 曾大本[2] 

机构地区：[1]清华大学力学工程系,北京100084 [2]清华大学机械工程系,北京100084

出　　处：《金属学报》2001年第10期1031-1034,共4页Acta Metallurgica Sinica

基　　金：清华大学机械工程学院重点基金

摘　　要：采用自制的流变装置进行瞬态流变实验，研究了Ａ３５６合金剪切速率阶梯变化对液－固温区不同初生α相形态瞬态 流变行为的影响．初始剪切速率为 ３６７．３ ｓ－１，剪切速率阶梯变化值分别为：５０．２，８３．７，１１８．６，１４１．８和 １９５．３ ｓ－１．结果表 明，剪切速率由较低值向初始值阶梯变化时，剪切应力首先出现瞬时峰值，并且随着剪切过程的进行剪切应力逐渐降低至稳定态． 对实验结果进行曲线拟合，得出剪切应力与时间的瞬态流变经验方程式：Ｔ－Ｔｓ＝Ｔｐｅ－ｋｔ，以及方程参数与半固态合金初生α 相形态和剪切速率的关系．The influence of step variation of shear rate on transient rheological behavior of semisolid A356 alloy with different morphologies of primary alpha-phase was explored through the use of rest time experiment by a self-designed rheometer. The initial shear rate was 367.3 s(-1), the variation values of shear rate were 50.2, 83.7, 118.6, 141.8 and 195.3 s(-1) respectively. Results indicated that the shear stress changed gradually from the transient peak value to its steady-state value while the shear rate altered from the given value to that of the initial shear rate. Empiric transient rheological equation, tau - tau(s) = tau(Deltap) e(-kt), which is used to describe the relations of shear stress, shear time, shear rate and morphology of primary a-phase, was obtained by ways of regression analysis.

关 键 词：半固态合金 瞬态流变行为 剪切速率阶梯变化 表观粘度 A356合金 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG115.9[金属学及工艺—金属材料]