Ta-7.5%W合金箔材的退火组织与性能

Microstructures and properties of annealed Ta-7.5%W alloy foils

通过力学性能测试、X线衍射和EBSD(电子背散射衍射分析)等方法研究Ta-7.5%W(质量分数)合金箔材在真空中1 200℃下退火1 h后的力学性能、织构和微观组织。研究结果表明:退火态的Ta-7.5%W合金箔材在沿着横向和轧向拉伸过程中表现出各向异性,其中轧向的抗拉强度达到753 MPa,伸长率达到13.4%,轧向的性能均优于横向性能,这是由于样品中主要织构组分的晶粒沿横向和轧向拉伸开启的滑移系是不一样的。样品中主要形成了3类织构,分别为轧面法向平行于<100>的θ-纤维织构、轧面法向平行于<111>的γ纤维,还有轧向平行于<110>的α纤维织构,其中主要的织构为(112)[1 10]和(111)[1 21],所占的体积分数分别10.2%和11.2%;由不同取向晶粒中的线取向差分布图分析可以看出(111)[1 21]取向的晶粒形成的位错亚结构之间的取向差很大,最大达到8.3°,亚晶之间的平均取向差也达到7°;(001)[1 10]取向的晶粒中形成的位错亚结构之间的取向差小很多,取向差最大也只有2.2°,平均取向差只有1.7°。

The properties, texture and microstructure of the annealed Ta-7.5%W （mass fraction） alloy foils were investigated by the analysis of mechanical properties testing, X-ray, and EBSD. It is found that the annealed Ta-7.5%W alloy foils are anisotropy when tensiling along the RD（rolling direction） and TD（transverse direction）. The tensile strength and elongation in the RD direction is 753 MPa and 13.4%, respectively, which are better than those in the TD direction, since the activation of slip systems is different in the main texture components. The EBSD （electron backscattered diffraction） results show that there are mainly three kinds of microtextures formed in the samples, which are 0-fibre with ND（normal direction）//〈100〉, y-fibre with ND/,/〈111〉 and a-fibre with RD//〈110〉. The main texture components are （112）[110] and （111）[121 ], and the volume fractures of which are 10.2% and 11.2%, respectively. Through the analysis of misorientaion profile of two particular texture components, it is shown that the misorientation between the subgrains in （11 I）[ 121 ] grain is very large with a maximum value of 8.3° and the average misorientation in this grain is 7° while the misorientation between the subgrains in （001）[ 110 ] is much smaller. The maximum and average misorientation in （001）[ 1 TO ] are 2.2° and 1.7°, respectively.