Fabrication and deformation behavior of a novel laminated TiAl matrix composite
Fabrication and deformation behavior of a novel laminated TiAl matrix composite
复制标题
DOI：
10.1016/j.msea.2021.141603
复制
发表时间：
2021-07
期刊：
影响因子：
--
通讯作者：
Xuesong Yang;Xuewen Li;Youhong Peng;Donghai Li;Tongtong Zhang;G. Fan;Chao Xu;Hao Wu;J. Zhang
中科院分区：
文献类型：
--
作者：
Xuesong Yang;Xuewen Li;Youhong Peng;Donghai Li;Tongtong Zhang;G. Fan;Chao Xu;Hao Wu;J. Zhang
双相钛铝化合物因其优异的热物理性能而在高温结构领域有着广泛的应用。本文采用热压和反应退火工艺制备了一种由等轴晶层（EGLs）和全层片晶层（FGLs）交替排列组成的新型TiAl基层状复合材料（LMC）。在微观结构剪裁之后，LMC在850 °C下表现出良好的强度和延展性的组合。实验表明，热残余应力的制造过程中引起的具有周期性分布的层。残余应力与外加应力的竞争改变了应力状态，从而激活了Ti3Al孪晶，有利于协调交替组元层间的不相容性。LMC中的层状结构显著提高了LMC的抗裂性能。裂纹萌生主要发生在EGL或层界面。然而，它们被层合结构有效地约束。相反，这些密集的微裂纹可以缓解应力集中，提高变形稳定性。本文的研究工作将丰富对TiAl合金应力介导变形行为的认识，并为高性能金属间化合物层合复合材料的设计提供指导。
Two-phase titanium aluminides are desirable for a wide range of high-temperature structural applications for their excellent thermo-physical properties. In this paper, a novel laminated TiAl matrix composite (LMC) consisting of alternating equiaxed grain layers (EGLs) and fully-lamellar grain layers (FGLs) has been fabricated successfully by hot-pressing and subsequent reaction annealing. After microstructure tailoring, the LMC exhibited a good combination of strength and ductility at 850 °C. Experiments demonstrated that the thermal residual stress induced by the fabrication process had a periodic distribution across the layers. The competition between residual stress and externally applied stress changed the stress state and accordingly the Ti3Al twining was activated, which benefited the accommodation of the incompatibility between alternating constituent layers. The crack tolerance was remarkably improved by layered structure in the LMC. Crack initiation occurred mainly in either the EGLs or the layer interface. However, they were constrained effectively by the laminated structure. Instead, these dense microcracks may relief the stress concentration and improve the deformation stability. This work is expected to enrich the current understanding on the stress-mediated deformation behavior of TiAl alloys, and provide guidance towards design of high-performance intermetallic laminated composites.