(南昌航空大学 航空制造工程学院，南昌 330063)
摘 要: 本文采用OM、SEM和高温蠕变性能测试等技术手段，研究了蠕变温度对真空差压分级加压铸造ZL114A合金高温蠕变性能的影响。结果表明：在同一分级加压压差下，当蠕变温度较低时，蠕变空洞生长困难，蠕变变形量较小。在相同的蠕变条件下，随着分级加压压差的增加，在晶界上偏聚的针状共晶硅组织转变为分布更均匀的棒状，蠕变空洞的数量减少，断口具有明显的韧性断裂特征。分级加压压差为185 kPa的试样，在进行50 h的蠕变后仍未断裂，高温蠕变性能获得极大的改善。
关键字: 真空差压铸造；分级加压压差；高温蠕变；断口形貌
（School of Aeronautic Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China）
Abstract:The effect of creep temperature on the high temperature creep properties of vacuum counter-pressure graded pressure casting ZL114A alloy was investigated by optical microscopy(OM), scanning electron microscopy (SEM) and high temperature creep properties test. The results reveal that the growth of creep voids is difficult at a lower creep temperature under the same graded pressure difference, resulting in a lower amount of creep deformation. On the other hand, the eutectic silicon which segregation on the grain boundary transforms from acicular to uniformly distributed rod-like tissue with the increase of graded pressure difference under the same creep conditions, meanwhile, the number of creep voids decreases, and fracture shows a characteristic of ductile fracture. The experiment indicates that the sample with a graded pressure difference of 185 kPa does not rupture after 50 h of creep which proves that the high temperature creep performance is greatly improved.
Key words: vacuum counter-pressure casting; graded pressure difference; high temperature creep; fracture morphology
