摘要
采用热分析(DSC)、扫描电镜(BSEM)、X射线衍射(XRD)、维氏硬度等测试手段,系统地研究了固溶处理后的高Nb-TiAl合金在1000~1300℃时效过程中的相变与组织演变。结果表明:高Nb-TiAl合金固溶处理后,组织偏析未完全消除,并存在α_2不稳定相;在连续升温过程中,在1192~1331℃之间,存在α_2→α相变和γ→α相变;在1200℃时效,合金显微组织为α_2/γ片层结构,在1300℃时效,显微组织为簇状结构。在1000℃与1100℃时效,随着时效时间的延长,合金的显微硬度呈现出先下降后上升的趋势,在1200~1300℃时效,随着时效时间的延长,合金的显微硬度先上升随后下降。
Phase transformations and microstructure evolution of high Nb-TiAl alloy after solution treating were investigated using differential scanning calorimetry(DSC),backscattered electron microscopy(BSEM),X-ray diffraction(XRD)and microhardness tester during the aging process from 1000 to 1300°C.The results indicate that the microstructure segregation of high Nb-TiAl alloy after solid solution treatment is not completely eliminated and metastableα_2 phase still exists.Two phase transformations,orderedα_2→disorderedαand tetragonalγ→hexagonalα,take place between 1192°C and 1331°C during continuous heating.The microstructure of the alloy is lamellar when the sample is aging treated at 1200°C,while it is clustered at 1300°C.The microhardness of high Nb-TiAl alloy decreases firstly and then increases with the increasing of time when the alloys are aging treated between 1000°C and 1100°C;conversely,the hardness increases firstly and then decreases as time goes on when the treating temperature ranges from 1200°C to 1300°C.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2017年第S1期91-94,共4页
Rare Metal Materials and Engineering
基金
江苏省材料科学工程优势学科(PAPD)
国家国际科技合作专项(2015DFA51430)
国家材料环境腐蚀平台
