(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 冶金与环境学院，长沙 410083；
3. 中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 利用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)和拉伸力学试验等方法对铸锭冶金Ti-45Al-7Nb-0.3W合金热轧板材力学性能的各向异性进行研究。结果表明：Ti-45Al-7Nb-0.3W合金热轧板材具有明显的力学性能各向异性，在室温条件下，沿轧制方向的屈服强度σRD为445 MPa，高于沿横向的屈服强度σTD；在800 ℃条件下，σRD为522 MPa，低于σTD。织构和显微组织表明：经热轧变形后，板材中存在明显{100}á010？立方织构，即面心四方γ晶胞的c轴平行于横向；在轧制纵截面上，板材显微组织表现为拉长的γ晶粒和α2/γ层片晶团；在横截面上，板材显微组织表现为等轴的γ晶粒和α2/γ层片晶团。Ti-45Al-7Nb-0.3W合金热轧板材力学性能的各向异性是由织构和显微组织的差异所致。
关键字: TiAl基合金；各向异性；织构；显微组织
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The anisotropy of mechanical properties of ingot metallurgical Ti-45Al-7Nb-0.3W alloy hot-rolling sheet was investigated by optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffractometry and tensile test. The results indicate that the hot-rolling sheet presents significant anisotropy of mechanical properties, at room temperature, the yield strength of rolling direction(RD) is 445 MPa, which is higher than that of the transverse direction(TD); while at 800 ℃, the yield strength of rolling direction(RD) is 522 MPa, which is lower than that of the transverse direction(TD). The texture and microstructure analysis results indicate that there exists a strong cube texture {100}á010？ in the rolling sheet, i.e., the á001？ c-axes of the tetragonal γ-TiAl unit cells parallel to the TD. And along the rolling direction the microstructure of TiAl alloy hot-rolling sheet are composed of elongated γ grains and α2/γ lamellar colonies, while along the transverse direction the microstructure is composed of elongated γ grains and α2/γ lamellar colonies. The existing texture and difference of microstructure result in the mechanical anisotropy of Ti-45Al-7Nb-0.3W alloy hot-rolling sheet.
Key words: TiAl alloy; anisotropy; texture; microstructure
