Effect of initial microstructure on the micromechanical behavior of Ti-55531 titanium alloy investigated by in-situ high-energy X-ray diffraction
Effect of initial microstructure on the micromechanical behavior of Ti-55531 titanium alloy investigated by in-situ high-energy X-ray diffraction
复制标题
DOI：
10.1016/j.msea.2019.138806
复制
发表时间：
2020-01
期刊：
影响因子：
6.4
通讯作者：
Yimin Cui;Chaohua Li;Changsheng Zhang;Runguang Li;Yang Ren;Wei-Wei Zheng-Wei;Yandong Wang
中科院分区：
文献类型：
--
作者：
Yimin Cui;Chaohua Li;Changsheng Zhang;Runguang Li;Yang Ren;Wei-Wei Zheng-Wei;Yandong Wang
Ti-55531高强度钛合金的显微组织特征，包括相的形态和织构，对合金的力学性能起着重要的作用。然而，从微观力学方面的基本理解仍然缺乏。本文采用高能X射线衍射技术研究了Ti-55531合金的显微组织对微观力学行为的影响。对Ti-55531合金的两种典型微观组织，测定了取向晶粒的微观力学行为，包括晶格应变。此外，还讨论了不同显微组织试样中α、β相之间的应力分配及内部应力的演化规律。结合显微组织表征，探讨了显微组织对力学性能影响的相应机理。结果表明，对于不同组织类型的试样，各相之间的应力分配有明显的差异。结果表明，在双模态组织（BM）试样中，α相的应力高于β相，而在层状组织（LM）试样中，β相的应力远高于α相。对于含有BM的试样，α相的形貌导致αp（初生α相）和αs（次生α相）的微观变形行为存在显著差异。针状α p沉淀相比等轴状αp沉淀相承受更高的应力。在这两个标本的晶间和相间的微观应力进行了定量评估。结果表明，<200>β相的//LD纤维织构导致含BM试样中较高的晶间应力。LM试样的界面微应力更为显著。结合原位HEXRD和微观结构表征，本研究从微观力学行为的角度提供了一个基本的理解微观结构和力学性能之间的关系。
Microstructure features including the morphology and texture of constituent phases play an important role in the mechanical properties of Ti-55531 high strength titanium alloy. However, the underlying understanding from the micromechanical aspect is still lacking. In the present work, the effect of microstructure on the micromechanical behavior of Ti-55531 alloy was investigated by high-energy X-ray diffraction. For two typical microstructures of Ti-55531 alloy, the micromechanical behavior including lattice strains of oriented grains are determined. Furthermore, the stress partitioning between α and β phase and internal microstress evolution in the specimens with different microstructures are discussed. In combination with the microstructure characterization, the corresponding mechanism for microstructure influence on the mechanical properties is discussed. It is found that, for the specimens with different types of microstructures, stress partitioning between constituent phases is obviously different. The results show that the α phase stress is higher than that of β phase in the specimen with the bimodal microstructure (BM), while the β phase is subjected to much higher stress than α phase in the specimen with the lamellar microstructure (LM). For the specimen with BM, the morphology of α phase leads to a remarkable difference in the microscopic deformation behavior between αp(primary α phase) and αs(secondary α phase). It is suggested that the acicular αsprecipitates bear higher stress than equiaxed αp. The intergranular and interphase microstresses in both specimens have been quantitatively evaluated. The results show that the <200>//LD fiber texture of β phase leads to higher intergranular microstress in the specimen with BM. The interphase microstress is more remarkable in the specimen with LM. Combining the in-situ HEXRD and microstructure characterization, the present study provides a fundamental understanding of the relationship between microstructure and mechanical properties from the perspective of micromechanical behavior.