中文摘要：

采用金相显微镜（OM）、扫描电子显微镜（SEM）、X射线衍射仪（XRD）和力学拉伸试验等方法对粉末冶金Ti-45Al-7Nb-0.3W合金板材的微观组织以及力学性能进行了研究.结果表明,热等静压态合金的组织为近γ组织,其织构强度呈随机分布;轧态合金的组织为双态组织,板材中存在较强的{ 100}＜010＞立方织构和较弱的{110} ＜112＞黄铜型织构;室温下,不同拉伸方向上该高Nb-TiAl合金板材的屈服强度在708 ～ 725 MPa之间,延伸率均不到1％;高温条件下,随温度的升高,合金板材的强度逐渐降低,延伸率逐渐升高,最高为15.6％,其塑脆性转变温度在800～850℃之间;粉末冶金Ti-45Al-7Nb-0.3W合金板材的力学性能呈现出相对较弱的各向异性,可以归因于{100}＜010＞立方织构.

英文摘要：

Microstructure and mechanical properties of powder metallurgical Ti -45A1 -7Nb -0. 3W alloy sheet were investigated by optical microscopy （ OM ）, scanning electron microscopy （ SEM ）, X - ray diffraction and tensile testing. Results indicate that the microstructure of as - HIPed alloy was near gamma, which nearly had a random texture. The microstrueture of as-rolled alloy was duplex,which had a relatively strong /100} 〈010 〉 cube texture and a weak {110} 〈 11-2 〉 brass texture. At room temperature,for high Nb -TiA1 alloy sheet,yield strength in the range of 708 ~ 725 MPa and below 1% plastic elongation were obtained at different tension direction. At elevated temperature ,the strength decreased with the increasing temperature, while the plastic elongation increased with a maximum of 15.6%. The brittle - plastic transition temperature was between 800 ℃ and 850 ℃. The relatively weak anisotropy of mechanical properties can be attributed to the cube texture {100} 〈010 〉.