(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué) 冶金與環(huán)境學(xué)院，長沙 410083；
3. 中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 利用光學(xué)顯微鏡(OM)、掃描電子顯微鏡(SEM)、X射線衍射儀(XRD)和拉伸力學(xué)試驗(yàn)等方法對鑄錠冶金Ti-45Al-7Nb-0.3W合金熱軋板材力學(xué)性能的各向異性進(jìn)行研究。結(jié)果表明：Ti-45Al-7Nb-0.3W合金熱軋板材具有明顯的力學(xué)性能各向異性，在室溫條件下，沿軋制方向的屈服強(qiáng)度σRD為445 MPa，高于沿橫向的屈服強(qiáng)度σTD；在800 ℃條件下，σRD為522 MPa，低于σTD。織構(gòu)和顯微組織表明：經(jīng)熱軋變形后，板材中存在明顯{100}á010？立方織構(gòu)，即面心四方γ晶胞的c軸平行于橫向；在軋制縱截面上，板材顯微組織表現(xiàn)為拉長的γ晶粒和α2/γ層片晶團(tuán)；在橫截面上，板材顯微組織表現(xiàn)為等軸的γ晶粒和α2/γ層片晶團(tuán)。Ti-45Al-7Nb-0.3W合金熱軋板材力學(xué)性能的各向異性是由織構(gòu)和顯微組織的差異所致。
關(guān)鍵字: TiAl基合金；各向異性；織構(gòu)；顯微組織
（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
