晶粒尺寸和片层厚度对全片层γ-TiAl基合金屈服强度的影响  

Effects of Grain Size and Lamellar Thickness on Yield Strength of Fully Lamellar γ-TiAl Based Alloys

作　　者：苏继龙[1] 林高飞[1] 郑书河[1] 

机构地区：[1]福建农林大学机电工程学院,福州350002

出　　处：《航空材料学报》2009年第4期1-5,共5页Journal of Aeronautical Materials

基　　金：福建省科技厅资助省属高校项目(2005K033);福建省自然科学基金项目(2008J0141)

摘　　要：基于多位错塞积理论,建立了全片层γ-TiAl基合金屈服强度尺度效应的解析预测细观力学模型,得到了全片层γ-TiAl基合金屈服强度的计算公式并详细分析了晶粒尺寸d和片层厚度λ对屈服强度的影响关系,数值预测结果趋势与已有的试验结果相吻合。主要结论是:γ-TiAl基合金屈服强度对晶粒大小d变化不敏感,而对片层厚度λ具有强烈的依赖关系,随着片层厚度的减小,屈服强度明显增大,表现出显著的尺度效应;屈服强度与片层厚度之间的制约关系在一定的片层尺度范围内符合Hall-Petch关系。值得注意的是,当片层尺寸λ细化至90nm时,γ-TiAl基合金材料的屈服强度达到一极限饱和值,这一极限饱和值约为1000MPa。An analytical method, based on the multiple-piled-up dislocation model, was presented to investigate the effects of the lamellar thickness（ λ） and the grain size（d） on the yield strength of fully lamellar γ-TiAl based alloys. A simple formula was derived analytically to describe the relation of microstructural parameters to the yield strength , which gave a good agreement with the experimental results. It is found that yield strength is not sensitive to the grain size. Meanwhile, the numerical results show that the yield strength of fully lamellar γ-TiAl based alloys depends strongly on the lamella thickness, it increases with the decrease of the lamellar spacing（λ） , and the yield strength has significantly size-dependent property. Also, Hall-Peteh relation has been holden between lamellar spacing （λ） and the yield strength of the alloys within a certain scale range of lamellar spacing. Furthermore, it is worth noting that the yield strength saturates at a value of about 1000MPa when the lamellar thickness is less than the critical scale of 90nm.

关 键 词：Γ-TIAL基合金 屈服强度 位错 片层厚度 晶粒尺寸 

分 类 号：TH142.2[一般工业技术—材料科学与工程] TG146[机械工程—机械制造及自动化]