中速生长条件下单晶高温合金组织及偏析研究  

MICROSTRUCTURE AND MICROSEGREGATION OF Ni-BASE SINGLE CRYSTAL SUPERALLOY SOLIDIFIED AT MEDIUM COOLING RATE

作　　者：杜炜[1] 魏朋义 李建国[1] 傅恒志[1] 孙家华[3] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072 [2]北京航空材料研究院 [3]冶金工业部钢铁研究总院,北京100081

出　　处：《金属学报》1998年第4期356-361,共6页Acta Metallurgica Sinica

基　　金：国家航空科学基金

摘　　要：本文利用高梯度定向凝固设备研究了镍基单晶高温合金在中等凝固速率条件下枝晶组织和偏析变化的基本规律.实验发现采用高梯度定向凝固技术可以得到具有超细枝晶组织的单晶高温合金材料，枝晶偏析在低速生长时随冷却速率的增加而增加，而在高速生长时形成的超细枝晶组织中，枝晶偏析随冷却速率的增加而减小.With the help of high temperature-gradient directional solidification equipment (HGDS), the microstructure and microsegregation of Ni-base single crystal superalloy CMSX-2 solidified at the cooling rates from below 1 K/s to 20 K/s were investigated. The morphology of γ' precipitates and γ/γ'eutectic in the specimens were examined. The results show that, withthe increase of the cooling rate, the primary dendrite arm spacing is greatly refined to 38 μm,just as one-tenth as that by HRS processing. The microsegregation increases and then decreaseswith the increase of cooling rate. In the superfine columnar dendrite , the γ' precipitate is very fine, the amount of γ/γ' eutectic is much fewer and its' size is very small.

关 键 词：单晶 高温合金 凝固组织 枝晶偏析 

分 类 号：TG113.12[金属学及工艺—物理冶金] TG132.32[金属学及工艺—金属学]