单晶高温合金DD6再结晶组织及其对持久性能的影响  

MICROSTRUCTURE OF RECRYSTALLIZATION AND THEIR EFFECTS ON STRESS RUPTURE PROPERTY OF SINGLE CRYSTAL SUPERALLOY DD6

作　　者：熊继春[1] 李嘉荣[1] 孙凤礼[2] 刘世忠[1] 韩梅[1] 

机构地区：[1]北京航空材料研究院先进高温结构材料重点实验室,北京100095 [2]北京航空材料研究院第三研究室,北京100095

出　　处：《金属学报》2014年第6期737-743,共7页Acta Metallurgica Sinica

摘　　要：对单晶高温合金DD6进行表面吹砂处理,然后分别在1100,1200和1300℃保温4h,研究了不同加热条件下DD6合金的再结晶组织及其对持久性能的影响.结果表明,DD6合金吹砂试样1100℃加热4 h形成胞状再结晶组织,胞状再结晶晶界前沿的基体中存在大量的位错缠结,合金的持久寿命略微降低;1200℃加热4 h形成胞状再结晶与等轴再结晶同时存在的混合型再结晶组织,合金的持久寿命降低;1300℃加热4 h形成等轴再结晶组织,等轴再结晶晶界上发现碳化物析出,合金的持久寿命严重降低.带有等轴再结晶组织的持久试样的断口形貌为沿晶断口,带有胞状再结晶组织的持久试样的断口形貌为韧窝断口,带有再结晶组织的试样裂纹起源于再结晶晶界.The specimens of single crystal superalloy DD6 were grit blasted and heat treated at 1100, 1200,and 1300 ℃ for 4 h at vacuum atmosphere respectively, then the microstructure of recrystallized DD6 alloy and their effects on the stress rupture performance were investigated. The results showed that cellular recrystallization nucleated in grit blasted samples heat treated at 1100 ℃ for 4 h, the dislocation tangles were found in the front of cellular recrystallization grain boundary in DD6 alloy, equiaxed recrystallization grains nucleated in grit blasted samples heat treated at 1300 ℃ for 4 h, and the carbides precipitate at the equiaxed recrystallization grain boundary, while the coexistence of equiaxed recrystallization grains and cellular recrystallization, defined as mixed recrystallization, occurred in the grit blasted samples heat treated at 1200 ℃ for 4 h. The cellular recrystallization reduced the stress rupture lives of DD6 alloy slightly, and the equiaxed recrystallization reduced stress rupture lives seriously, while the reduction degree of the stress rupture lives of the mixed recrystallization was between cellular recrystallization and equiaxed recrystallization. Besides this, with increase of depth of recrystallization and stress,the stresses rupture life decreased. It was also found that the fracture surface configuration was belonging to intergranular fracture with equiaxed recrystallization samples. The characteristic of the fracture surface changed to dimple fracture with cellular recrystallization samples, at all these condition the crack nucleated on the recrystallization grain boundaries of specimens during stress rupture process.

关 键 词：单晶高温合金 DD6 再结晶 组织 持久性能 

分 类 号：TG132.3[一般工业技术—材料科学与工程]