850℃等温时效对高Nb-TiAl合金组织和力学性能的影响  

Effects of Isothermal Aging at 850℃on Microstructure and Mechanical Properties of High Nb-TiAl Alloy

作　　者：李莹 李栋 常辉[2] 樊江磊 王永彪 LI Ying;LI Dong;CHANG Hui;FAN Jianglei;WANG Yongbiao(School of Mechanical and Electrical Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,China;College of Materials Science and Engineering,Nanjing Tech University,Nanjing 211816,China)

机构地区：[1]郑州轻工业大学机电工程学院,河南郑州450002 [2]南京工业大学材料科学与工程学院,江苏南京211816

出　　处：《热加工工艺》2024年第16期35-38,共4页Hot Working Technology

基　　金：河南省科技攻关项目(202102210451);郑州轻工业大学博士科研基金项目(2017BSJJ014,2017BSJJ015)。

摘　　要：采用光学显微镜、扫描电子显微镜、X射线衍射仪和显微硬度仪等手段,系统研究了850℃等温时效对高Nb-TiAl合金的显微组织及硬度的影响。结果表明:锻态高Nb-TiAl合金显微组织为近片层组织结构,片层团尺寸约为112μm,片层间距约为1.6μm,具有锯齿状晶界,主要由γ和α2相组成;合金在850℃等温时效分别为5 min、5 h、10 h、20 h的过程中,其显微组织主要由γ相、α2相和少量β相形成的片层组织结构组成,随着等温时间的延长,合金片层团和片层间距均存在明显的粗化现象;在不同的等温时效过程中,合金的表面皆表现出比较高的硬度值(420~460 HV),其显微硬度随保温时间的延长呈下降趋势。The microstructure and mechanical properties of high Nb-TiAl alloy exposed to isothermal aging at 850℃processing were investigated using optical microscope(OM),scanning electron microscope(SEM),X-ray diffractometer(XRD)and microhardness and other testing methods.The results indicate that the microstructure of the as-forged high Nb-TiAl alloy is a near-laminated structure with jagged grain boundary,the sheet mass size is about 112μm,and the interlamellar spacing is about 1.6μm.The microstructure of the alloy is mainly composed ofγphase andα2 phase.During an 850℃isothermal period of 5 min,5 h,10 h,20 h,respectively,the microstructure mainly consists of lamellar structures formed byγphase,α2 phase and a small amount ofβphase during the high-temperature aging.With the extended isothermal time,both the alloy sheet layer group and the sheet layer spacing have obvious coarsening phenomenon.In different isothermal time time,the surface of the alloy shows a relatively high hardness value(420-460 HV),and its microhardness decreases with the extension of the insulation time.

关 键 词：高Nb-TiAl合金 热处理 微观组织 显微硬度 

分 类 号：TG156.92[金属学及工艺—热处理]