初生相形态对半固态A356合金瞬态流变行为的影响  

Influence of Microstructure of Semi solid A356 Alloy on its Transient Rheological Behavior

作　　者：唐靖林[1] 曾大本[1] 

机构地区：[1]清华大学,北京100084

出　　处：《材料工程》2000年第8期43-46,共4页Journal of Materials Engineering

摘　　要：采用自行研制的流变设备进行间断剪切试验 ,研究了 A35 6半固态合金的初生相形态对其瞬态流变行为的影响。初生相形态分别为枝晶、退化枝晶以及颗粒晶。结果表明 ,对静置一段时间的半固态合金突施剪切 ,首先导致表观粘度出现峰值 ,随等温剪切过程的进行 ,表观粘度逐渐下降至平衡态。随着半固态 A35 6合金初生相由枝晶逐渐退化 ,瞬态剪切的峰值表观粘度显著减小 ,而表观粘度的衰减速率大幅度增加。回归分析表明 ,在恒剪切率、等温间断剪切条件下 ,半固态 A35 6合金的表观粘度变化规律符合幂方程。WT5BZ]Transient rheological behavior of semi solid A356 alloy was explored through the use of rest time experiment by a self designed rheometer The morphology of primary α phases was respectively dendrite, rosette and spheroid In the rest time experiments, abrupt shear resulted in peak viscosity which then drifted to an equilibrium or steady state with constant shearing The apparent viscosity evidently decreased along with the microstructure transforming from dendrite to spheroid Regression analysis was adopted to study the variation of apparent viscosity of semi solid alloy in the isothermal constant shear process Results indicated that semi solid A356 alloys fit the power law model in rest time experiments After abrupt shear, It would take much longer time for dendritic SSM to reduce viscosity to an equilibrium or steady state than that for semi solid alloys with spheroid and rosette

关 键 词：初生相 形态 A356合金 半固态合金 瞬态流变行为 触变性 表观粘度 

分 类 号：TG113.25[金属学及工艺—物理冶金]