钛合金材料蠕变特性的理论与试验研究

Theoretical and experimental investigations for creep properties of titanium alloy materials

钛合金是深海工程装备的重要材料,在深海环境下会产生不同程度的蠕变变形。该文针对双态组织和网篮组织TC4 ELI钛合金材料,在宏观和微观两个方面开展钛合金蠕变试验研究。开展多组应力水平下的钛合金压缩蠕变试验,绘制蠕变曲线,对传统的Norton方程进行修正,基于最小二乘法拟合饱和蠕变临界应力值和蠕变应力指数,给出初始蠕变阶段和稳态阶段的蠕变本构关系。同时,基于OM(光学显微镜)、XRD(X射线衍射)、TEM(透射电镜)和SEM(扫描电镜)观察,给出TC4 ELI钛合金材料的压缩蠕变微观机理。

Titanium alloys,the critical material of deep-sea engineering equipment,will produce different levels of creep deformations in deep-sea environment.Experimental investigations of creep are developed in the aspect of macroscopic and macroscopic in allusion to the duplex microstructure and the basket-weave microstructure.The creep curves are plotted,and traditional Norton equation is modified based on compressive creep tests of titanium alloys at multigroup stress levels.Critical stresses of saturated creep and stress exponents are fitted based on least square method while constitutive relation for creep in the stage of transient creep and steady creep are presented.Simultaneously,based on the methods of OM(optical microscope),XRD(X-Ray diffraction),TEM(transmission electron microscope)and SEM(scanning electron microscope),microscopic mechanism of compressive creep for the TC4 ELI titanium alloy is elaborated.