大尺寸高铌钛铝合金铸锭的组织  

Microstructure of High Nb Containing TiAl Alloy on Large Scale

作　　者：徐向俊[1] 林均品[1] 王艳丽[1] 宋西平[1] 林志[1] 陈国良[1] 

机构地区：[1]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《铸造》2006年第3期300-303,共4页Foundry

基　　金：国家自然科学基金(50274005)资助

摘　　要：通过金相、扫描电镜、投射电镜、X-射线和能谱等方法对真空自耗+真空自耗凝壳复合熔炼工艺制备的Ti-45%Al-(8～9)%Nb-(W,B,Y)(原子分数)合金大尺寸铸锭的组织进行了分析。结果表明,铸锭组织是由表面细小均匀和大部分存在微观偏析的γ/α2片层团和少量分布于片层团间的γ和β(B2)晶粒组成的近层片组织(NL)。大部分组织含有明显的γ聚集区,片层团的尺寸为75μm,平均片层厚度为700nm。β以不规则形状存在于片层团间或以片状和块状存在于片层团内。另外有大量长达60μm的棒状和针状硼化物。Microstructure of Ti-45Al-8.5Nb- （W, B, Y） （at.%） alloy ingot on large scale melted using vacuum consumable melting followed by vacuum consumable skull melting has been studied by using optical microscopy （OP）, scanning electron microscopy （SEM） , transmission electron microscopy （TEM）, X-ray diffraction （XRD）, energy dispersive spectrometry （EDS）. The results show that the microstructure of the ingot is near lamellar microstructure （NL） composed of finer lamellar colonies for near surface zone and coarser lamellar colonies for the majority zone and γ,β（B2） phases. For the majority zone of the ingot γ-rich zone is present, and lamellar colony size is about 75μm with the average lamellar spacing of 700 nm. β phase exists either on the boundaries of the lamellar colonies in irregular morphology or within the lamellar colonies in lamellar or blocky morphology. There also exist some titanium boride ribbons and needles longer than 60 μm.

关 键 词：高铌TIAL合金 铸锭 组织 偏析 

分 类 号：TG113.1[金属学及工艺—物理冶金]