一种新型定向凝固镍基高温合金抗热腐蚀性能的研究  

STUDY ON HOT CORROSION RESISTANCE OF A NEW DIRECTIONAL SOLIDIFICATION Ni-BASED SUPERALLOY

作　　者：宁礼奎[1,2] 郑志[2] 谭毅[1] 刘恩泽[2] 佟健[2] 于永泗[1] 王华[3] 

机构地区：[1]大连理工大学材料科学与工程学院,大连116023 [2]中国科学院金属研究所,沈阳110016 [3]中航工业西安航空发动机(集团)有限公司,西安710021

出　　处：《金属学报》2009年第2期161-166,共6页Acta Metallurgica Sinica

摘　　要：研究了新型定向凝固镍基高温合金DZ68的抗热腐蚀性能,并与K438合金进行了比较.结果表明:热处理态DZ68合金组织中几乎没有(γ+γ′)共晶,碳化物尺寸小,其整体组织比较均匀;在热腐蚀过程中发生比较均匀的腐蚀,其外腐蚀层的腐蚀产物主要是(Ni,Co)Cr_2O_4,内腐蚀层的腐蚀产物主要是Al_2O_3.热处理态K438合金组织中存在较多的(γ+γ′)共晶和数量较多、尺寸较大的长条状碳化物,组织均匀性较差;在热腐蚀过程中发生不均匀腐蚀,其外腐蚀层的腐蚀产物主要是NiO,内腐蚀层的腐蚀产物主要是CrS.两种合金中Ti元素的偏析有促进其它元素偏析的倾向,使合金组织的均匀性恶化,热腐蚀均匀性变差.在本实验条件下,DZ68合金的抗热腐蚀性能略好于K438合金.The hot corrosion resistance of a new directional solidification （DS） Ni-based superalloy DZ68 was studied and compared with K438 alloy. The results indicate that the microstructure of DZ68 alloy is more uniform than K438 alloy after heat treatment. There are small size carbides in the microstructure of DZ68 alloy after heat treatment, but there are big size carbides and a lot （γ＋γ′） eutectic in the microstructure of K438 alloy. The hot corrosion of DZ68 alloy is uniform, and the corrosion products are mainly （Ni, Co）Cr2O4 and Al2O3. More （Ni, Co）Cr2O4 exists in outer corrosion layer and more Al2O3 exists in inner corrosion layer. For the K438 alloy the hot corrosion is not uniform, NiO is the mainly corrosion product in outer corrosion layer and CrS is the main corrosion product in inner corrosion layer. Moreover, the segregation of Ti can induce segregation of other elements in the two alloys, which leads to a severe local corrosion of alloys. Under the same experimental condition, the corrosion resistance of DZ68 alloy is a little better than that of K438 alloy.

关 键 词：DZ68 热腐蚀 高温合金 

分 类 号：TG146.15[一般工业技术—材料科学与工程] TG172.62[金属学及工艺—金属材料]