Ti-26Nb-28Ta-5.5Zr合金室温压缩变形过程中微观组织变化规律

Microstructures Variation of Ti-26Nb-28Ta-5.5Zr Alloy during Compression at Room Temperature

借助d电子理论计算,设计并制备了具有较高Kβ稳定参数的生物相容性β型Ti-26Nb-28Ta-5.5Zr(%(质量分数),Kβ～1.61)合金。综合利用万能电子试验机测试、显微硬度测试、X射线衍射分析和透射电子显微学观察等方法,研究了该合金固溶态时的压缩性能、变形机制以及不同变形量对应的显微结构特征。结果表明:固溶态β型Ti-26Nb-28Ta-5.5Zr合金具有较好的塑性,其屈服强度约为450 MPa。当变形量为7%时,其形变机制为位错滑移;当形变量为50%时,严重影响变形结构特征的塑性变形机制主要为应力诱发α″马氏体相变;而当形变量为75%时,除了α″马氏体相变、还观察到明显的非均匀局域化变形。

With the aid of d-electron alloy theory calculation,a β-type biocompatible Ti-26Nb-28Ta-5.5Zr（%（mass fraction）,Kβ～1.61） alloy with higher Kβ stability parameter was designed and prepared.Electronic universal testing machine compressing,microhardness testing,X-ray diffraction examination and transmission electron microscopy observations were applied to investigate the mechanical properties under compression,deformation mechanisms and deformation microstructural characteristics for the solution-treated Ti-26Nb-28Ta-5.5Zr alloy.The results showed that,the β-type Ti-26Nb-28Ta-5.5Zr alloy in solution-treated state had good plasticity and its compressive yield strength was 450 MPa.Dislocation glide was the dominant mechanism when the amount of compression deformation was 7%.Stress-induced α″ martensite transformation was the main plastic deformation mechanism which could have a strong influence on the characteristic of deformed microstructure when the amount of compression was 50%.In addition to the stress-induced α″ martensite transformation,non-uniform localized deformation was also found to occur when deformation amount was 75%.