真空自耗熔炼制备Ti-22V-10Cr-2Zn-xY合金的组织和力学性能分析

采用真空自耗熔炼制备Ti-22V-10Cr-2Zn-xY合金,并对其进行挤压和热处理。通过实验测试的手段研究不同Y元素添加量下钛合金的组织,力学性能,热稳定及蠕变性能。研究结果表明:加入Y后合金再结晶过程中在条型Y元素边缘形成了数量众多的细小晶粒,晶粒组织均匀性也获得较大改善。相对于室温,合金在600℃高温条件下发生了拉伸强度减小,获得更优塑性。增大Y元素加入量后,热稳定性能试样发生拉伸强度先提高后降低,屈服强度不断减小,获得了更优塑性。对试样进行热暴露处理,晶界区域出现了较多的α相,引起脆性沿晶断裂,塑性也明显降低。Y比例在0.1%与0.2%条件下的合金热稳定保持基本一致。经过600℃高温作用后,合金组织内形成了空洞结构,引起蠕变性与持久性的下降。含有0.1%Y元素的试样具备最优的蠕变性能,并且持久性也达到最佳状态。

Property Modification of Vacuum Consumption-Molten Ti-V-Cr Alloy by Y-Doping

The Y-doped Ti-22 V-10 Cr-2 Zn alloy,an advanced spacecraft engine material synthesized by vacuum self-consumption melting,was extruded and annealed.The influence of the Y-content on the microstructures and mechanical properties was investigated with scanning electron microscopy.The preliminary results show that the Y-doping had a major impact.Specifically, as the Y-content increased,the tensile-strength and cross-sectional area shrinkage ratio,measured at 23℃ and 600℃,changed in an increase-decrease mode;the elongation ratio significantly increased;and the yield-strength slowly decreased,resulting in improved plasticity.Doped at Y-0.1 wt%,the Ti-22 V-10 Cr-2 Zn-xY alloy displayed the best durability and creep behavior.The Y-doping considerably affected the microstructures,for example,formation of small grains at the Y-stripes edges,grain-size reduction and improvement of uniformity.We concluded that the Y-doping induced reconstruction of microstructures explains the modification of mechanical properties of Ti-V-Cr alloy.