The effect of tungsten content on the rolling texture and microstructure of Ta-W alloys

The effect of tungsten content on deformation texture and microstructure of Ta-W alloy is studied. It is found that the increase of tungsten content results in the strengthening of a-fiber and the weakening of gamma-fiber in Ta-W alloys. The volume fraction of gamma-fiber developed in Ta-10W alloy is lower than that in Ta-2.5W alloys. Meanwhile, a more significant through-thickness texture gradient is formed in Ta-10W alloy. The addition of tungsten has an important effect on the ability cross-slip of dislocations. Therefore, more dislocation loops and activated slip systems can be seen in Ta-2.5W alloy. The size of the dislocation cells in Ta-2.5W alloy is larger than that in Ta-10W alloy. As shear bands tends to appear in gamma-fiber, the density of shear bands in the Ta-2.5W alloy is much higher than that of Ta-10W alloy at the same reduction strain. Meanwhile, the wavelength of the wavy shear bands in Ta-10W alloy is smaller than that in Ta-2.5W alloy. In Ta-10W alloy, new grains with Goss orientation can be seen in periodic shear bands developed in {111} < 112 > orientations, which is different from that in Ta-2.5W alloy.

研究了钨含量对钽 - 钨合金变形织构和微观结构的影响。发现钨含量的增加导致钽 - 钨合金中α纤维增强，γ纤维减弱。Ta - 10W合金中形成的γ纤维的体积分数低于Ta - 2.5W合金。同时，Ta - 10W合金中形成了更显著的厚度方向织构梯度。钨的添加对位错的交滑移能力有重要影响。因此，在Ta - 2.5W合金中可以看到更多的位错环和激活的滑移系。Ta - 2.5W合金中位错胞的尺寸大于Ta - 10W合金。由于剪切带倾向于在γ纤维中出现，在相同的压下应变下，Ta - 2.5W合金中剪切带的密度远高于Ta - 10W合金。同时，Ta - 10W合金中波浪状剪切带的波长小于Ta - 2.5W合金。在Ta - 10W合金中，在{111}<112>取向发展的周期性剪切带中可以看到具有高斯取向的新晶粒，这与Ta - 2.5W合金不同。