硼化物原位自生增强TiAl基复合材料的组织演化、热变形行为及加工工艺设计（英文）

硼元素添加造成的相转变和硼化物析出等因素会对原位TiAl基复合材料显微组织演化及热变形行为产生影响。利用等温压缩实验、扫描电子显微技术以及透射电子显微技术等研究材料的动态再结晶和动态回复机制,并计算出其表现变形激活能为691.506 k J/mol。在1100～1200℃温度区间，再结晶γ和α晶粒的形核长大分别主导α₂→α相转变温度上、下的热变形行为。α相的动态回复主导材料在1250℃低应变速率下的热变形行为；同时，硼元素会提高α相含量,降低γ→α和α₂→α相转变温度,进而促进加载过程中回复α相晶粒的形核长大。根据新建的本构模型，对TiAl基复合材料的变形机制和加工工艺进行详细阐述.

Microstructure evolution,deformation behavior and manufacture design of TiAl matrix composites reinforced with in-situ borides precipitation

Phase transformation and borides precipitation caused by boron addition influence microstructure evolution and deformation behavior of in-situ TiAl matrix composites. Dynamic recrystallization mechanism and dynamic recovery mechanism were investigated by isothermal compression tests, scanning electron microscopy and transmission electron microscopy, etc. The value of apparent deformation activation energy (Q) of present composites is calculated to be 691.506 kJ/mol. In the temperature range of 1100?1200 °C, nucleation and growth of recrystallized γ and α grains promoted by TiB obstacles dominate the deformation below or above T_α2→α. The dynamic recovery of α phase dominates the deformation in condition with low strain rates at 1250 °C. Boron addition increases the fraction of α phase and decreases the transformation temperatures of γ→α and α₂→α, which promotes the nucleation and growth of recovered α grains during the loading. Deformation mechanisms and processing performance were also clarified based on the reestablished constitutive model.