FGH95粉末镍基合金蠕变期间位错网的形成与分析  

FORMATION AND ANALYSIS OF DISLOCATION NETWORK OF FGH95 POWDER METALLURGY Ni-BASED SUPERALLOY DURING CREEP

作　　者：谢君[1] 田素贵[1] 刘姣[1] 周晓明[2] 苏勇[1] 

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110870 [2]北京航空材料研究院先进高温结构材料国家重点实验室,北京100095

出　　处：《金属学报》2013年第7期838-844,共7页Acta Metallurgica Sinica

基　　金：国家自然科学基金资助项目51271125~~

摘　　要：采用TEM观察和衍衬分析研究了FGH95粉末镍基合金蠕变期间的位错组态.结果表明,蠕变初期,1/2〈110〉位错在γ基体{111}晶面开动,使位错不断增殖.蠕变稳态阶段,2组不同Burgers矢量的位错可能滑移至同一晶面并相遇,反应后形成六角位错网络,或在不同滑移晶面相交.形成具有四边形特征的位错网络.位错网的形成可降低位错可动性并抑制位错交滑移,提高合金蠕变抗力.蠕变后期变形特征是形变位错在γ/γ′界面位错网损坏处切入γ′相,切入γ′相的位错可发生分解,形成不全位错和层错的位错组态.Powder metallurgy Ni-based superalloys are used extensively in hot section of advanced aeroγengines due to their excellent comprehensive properties. During creep,the deformation mechanism of Ni-based superalloy depends on the alloy chemistry,morphology and volume fraction of γ phase and service conditions. Generally, the microstructure of FGH95 Ni-based alloy is closely related to the heat treatment regimes and its creep mechanism and properties are mainly determined by alloy cooling at oil path or molten salt bath. The difference of creep mechanism of molten salt cooling alloy from oil cooling alloy is that the dislocation networks may be formed in the matrix and therefore decrease the steady strain rate during creep to prolong the creep lifetime of the alloy. Unfortunately, the formation mechanism of dislocation networks in FGH95 Ni-based superalloy during creep is still unclear up to now. For this reason, by means of creep property measurement, TEM observation and diffraction contrast analysis, the formation of dislocation networks in FGH95 Ni-based superalloy during creep has been investigated. The results show that the 1/2〈110〉 dislocations are activated on the octahedral slip systems in the γ matrix of the alloy at initial stage of creep and then they continue to multiply through dislocation reaction. When the alloy enters into the steady stage of creep, two sets of slipping dislocations with different Burgers vectors would encounter on the same crystal plane to react and form a hexagonal dislocation network, or two sets of slipping dislocations on different planes would intersect to form a dislocation network with quadrangle cells. Generally speaking, the dislocation network formation can decrease the dislocation mobility and therefore restrain dislocation cross-slipping to enhance the creep resistance of the alloy. In the later stage of creep, the dislocations pile up near the regions of γ/γ’ interface and cause stress concentration, so that the deformed dislocations in the matrix shear and en

关 键 词：FGH95粉末镍基合金 蠕变 位错反应 位错网 衍衬分析 

分 类 号：TG111.8[金属学及工艺—物理冶金]