单晶Ni基合金高温蠕变期间γ'定向粗化驱动力的有限元分析  

FINITE ELEMENT ANALXSIS OF DRIVING FORCE OF γ~'-PHASE DIRECTIONAL COARSENING FOR A SINGLE CRYSTAL NICKEL-BASE SUPERALLOY DURING HIGH TEMPERATURE CREEP

作　　者：田素贵[1] 陈昌荣[2] 杨洪才[3] 胡壮麒[2] 

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110023 [2]中国科学院金属研究所材料疲劳与断裂国家重点实验室,沈阳110015 [3]东北大学材料与冶金学院,沈阳110006

出　　处：《金属学报》2000年第5期465-471,共7页Acta Metallurgica Sinica

摘　　要：为研究γ＇相定向粗化现象，采用有限元方法（ＦＥＭ）计算了单晶 Ｎｉ基γ和γ＇双相合金有／无外加载荷时的热错配应力及应变能密度．结果表明：外加载荷改变了γ和γ＇相内的ｖｏｎ Ｍｉｓｅｓ应力及应变能密度分布，与弹性应变相联系的共格应变能变化是γ＇相定向粗化的驱动力．外加拉伸或压缩应力，引起立方γ＇相不同界面晶格发生挤压或扩张应变，晶格的挤压应变可排斥γ＇相中原子半径较大的ＡＩ，Ｔａ等溶质元素；扩张的晶格可诱捕这些元素，以促进γ＇相的定向生长，因此，沿（１００）方向扩张晶格的法线方向是γ＇相形筏的生长方向．随γ＇相弹性扩张晶格应变及γ相粘滞塑性流变的增加，元素扩散及γ＇相形筏速率提高。By means of finite elements analysis, an investigation has been made for the directional coarsening of γ' precipitates in a single crystal nickel-base superalloy with [001] orientation during tensile or compressive creep at 1040℃.Results show that the strain energy change related to the elastic strain in the cubic γ'phase is the driving force for the γ'rafting. The elastic strain in the cubic γ' lattice results in the solid solubility change of the elements Ta and Al with bigger atomic radius. The extrusion or expansion strain in the lattice of the cubic γ' interfaces may repel or trap these atoms to promote the directional growth of the γ' phase.The normal direction of the enlarging lattice is the growing one of the γ' rafts.The rafting rate of γ' is enhanced with the increase of the viscoplastic flow in the γ phase and the elastic strain in the γ' phase, respectively.

关 键 词：单晶Ni基高温合金 蠕变 定向粗化 有限元 γ'相 

分 类 号：TG146.15[一般工业技术—材料科学与工程] TG132.32[金属学及工艺—金属材料]