钛合金与钛基复合材料第二相强韧化

Strengthening and Toughening Mechanisms of the Second Phase in Titanium Alloys and Titanium Matrix Composites

钛合金因具有比强度高、抗腐蚀性优两大突出优点,在航空、航天、航海、交通运输等领域具有广泛的应用,为进一步提高其耐热温度、弹性模量、耐磨性、强度以扩大应用范围,采用合金化、复合化引入第二相来实现强化目的。合金化可以实现固溶强化、纳米第二相强化及其带来的组织细化强韧化,通过变形还可以实现位错强化。复合化可以在钛合金中引入微米增强相,有效提高强化效果,但塑性大幅降低,通过调控增强相分布设计则可以有效解决塑性大幅降低的问题。如单一级准连续网状结构、两级网状-网状结构、两级层状-网状结构都表现出优异的室温与高温综合性能,在航空航天等领域具有广泛的应用前景,对飞行器减重设计提供重要支撑。钛合金与钛基复合材料力学性能的大幅提升将依赖于多级结构与多尺度增强相的设计与优化,与其相关的理论计算、数值模拟、高通量制备、强韧化机理、适用于多级多尺度结构的新理论、成形技术与应用将是研究重点。

Titanium alloys have been extensively used in the fields of aerospace,sailing,transportation et al.due to their high specific strength and corrosion resistance.To further enhance their high temperature durability,modulus,wear resistance and strength for more application,the secondary phase was introduced into titanium alloys by alloying and composite methods.The alloying method can generate solid solution strengthening effect,the secondary phase strengthening effect and grain refinement toughening effect.In addition,dislocation strengthening effect can be obtained by deformation.The composite method can effectively enhance the strength but sacrifice their ductility by introducing micro-scale reinforcement.It is fortunate to find that the problem of the composite low ductility can be solved by tailoring reinforcement distribution.The prepared composites with quasi-continuous single network microstructure,two-scale network-network microstructure or laminate-network microstructure exhibited superior mechanical properties at both room temperature and high temperature.Therefore,the composites can effectively support weight loss design of aerocraft,which will attract extensive application prospects in the fields of aerospace et al.The mechanical properties of titanium alloys and titanium matrix composites will be remarkably enhanced based on multi-scale hierarchical microstructure design and optimization.The corresponding theory calculation,numerical simulation,high-flux fabrication technology,toughening mechanisms,the forming technique and application will be the next research points.