摘要
利用金相显微镜(OM)、X射线衍射仪(XRD)和扫描电镜(SEM)及能谱分析(EDS)等测试方法研究Nb含量对铸造TiAl-xNb(x=1,3,5,7;原子分数,%)合金组织的影响。结果表明:Nb含量为1%时,TiAl-Nb合金铸锭组织主要为单相的γ组织;随Nb含量升高,合金组织主要为α2/γ层片组织;并在层片组织间存在2种偏析,分别是网状β相和γ相,合金的层片晶团平均尺寸逐渐增加,β相的体积分数逐渐升高;当合金中Nb的含量从1%增加到7%,层片晶团平均尺寸由89μm增加至190μm,β相的体积分数从1.9%增至12.9%;随合金中Nb含量增加,β相中Nb含量增加而Cr含量减少,γ相的偏析区域宽度变窄。
The effect of Nb content on the microstructure of as-cast TiAl-xNb (x=1,3,5,7; atom fraction,%) alloy was investigated by means of optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The results show that when the Nb content is 1%, the structure of as-cast TiAl-Nb is mainly singleγphase;with the increase of Nb content, the main structure of alloy isα2/γlamellar;there exist two kinds of segregations in lamellars, indicating to be webβphase andγphase, the average size of lamellar colony and the volume fraction ofβphase increase;with increasing Nb content from 1%to 7%, the average size of lamellar colony decreases from 89μm to 190μm, the area fraction ofβphase increases from 1.9%to 12.9%;with increasing Nb content in as-cast TiAl alloy, the Nb content in β phase increases while the Cr content in β phase decreases, the width of γ segregation decreases.
出处
《粉末冶金材料科学与工程》
EI
北大核心
2014年第3期367-372,共6页
Materials Science and Engineering of Powder Metallurgy
基金
国家重点基础研究发展规划(973计划)资助项目(2011CB605505)
国家自然科学基金资助项目(51174233)
关键词
TIAL合金
显微组织
偏析
Nb
TiAl alloy
Nb
microstructure
segregation