(南昌航空大學(xué) 航空制造工程學(xué)院，南昌 330063)
摘 要: 本文采用OM、SEM和高溫蠕變性能測試等技術(shù)手段，研究了蠕變溫度對真空差壓分級加壓鑄造ZL114A合金高溫蠕變性能的影響。結(jié)果表明：在同一分級加壓壓差下，當(dāng)蠕變溫度較低時，蠕變空洞生長困難，蠕變變形量較小。在相同的蠕變條件下，隨著分級加壓壓差的增加，在晶界上偏聚的針狀共晶硅組織轉(zhuǎn)變?yōu)榉植几鶆虻陌魻睿渥兛斩吹臄?shù)量減少，斷口具有明顯的韌性斷裂特征。分級加壓壓差為185 kPa的試樣，在進行50 h的蠕變后仍未斷裂，高溫蠕變性能獲得極大的改善。
關(guān)鍵字: 真空差壓鑄造；分級加壓壓差；高溫蠕變；斷口形貌
（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
