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
李莹 1李栋 2常辉 2樊江磊 1王永彪1
作者信息
- 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
- 折叠
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112 μm,片层间距约为 1.6 μm,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.
Abstract
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 112 μm,and the interlamellar spacing is about 1.6 μm.The microstructure of the alloy is mainly composed of γ phase and α2 phase.During an 850℃isothermal period of 5 min,5 h,10 h,20 h,respectively,the microstructure mainly consists of lamellar structures formed by γ phase,α2 phase and a small amount of β phase 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Key words
high Nb-TiAl alloy/heat treatment/microstructure/microhardness引用本文复制引用
基金项目
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)
郑州轻工业大学博士科研基金项目(2017BSJJ015)
出版年
2024
NETL
NSTL
万方数据