凝固参数对ZA27合金二次枝晶间距及抗拉强度的影响

Effect of solidification parameters on dendrite arm space and tensile strength of alloy ZA27

ZA2 7合金是近 2 0年来发展起来的一种新型铸造有色合金 ,具有较好的力学性能 ,但是 ,由于其很宽的结晶温区 ,组织多为的树枝晶 ,导致力学性能下降 .本文采用差热分析方法研究DTA曲线特征参数、凝固开始温度和冷却速率对二次枝晶间距λDAS的影响 ,同时使用IAS - 4图像分析系统分析了合金的微观组织 .结果表明 :DTA曲线峰高与二次枝晶间距呈线性关系 ;

ZA27 as a newtype nonferrous casting alloy has been studied in last two decades, but its wide solidification temperature range and fir tree like structure lead often to low properties. The effect of characteristic parameters on differential thermal analysis curve, solidification setup temperature and cooling rate on dendrite arm space (λ DAS ) was studied, and IAS-4 Image Analysis System was used for microstructural examination. It is shown that the relationship between peak height H on the DTA curve and λ DAS has approximately a linear character, but the relationship between cooling rate u and λ DAS  has an exponenfial manner.