多级结构的金属材料强韧化机理研究进展

Research on the Strengthening and Toughening Mechanism of Metallic Materials with Multiscale Hierarchical Structure

强度和塑韧性是金属结构材料主要的性能指标,然而通常会出现强度与塑韧性倒置的现象,即传统的固溶强化、纳米晶强化、弥散强化和加工硬化在追求强度的同时会不可避免地牺牲金属材料的塑韧性。根据多级多尺度仿生结构可协同提高强度和韧性的思路,系统介绍了两级Ti-TiB w/Ti复合材料、不锈钢复合板、多层复合钢、层/网耦合结构钢和超细纤维晶钢的构型设计,并揭示其强韧化机理和断裂机制,通过改变裂纹的扩展方式与裂纹的竞争机制,以及残余内应力的释放等途径,有效实现材料的强韧化,可为金属材料强韧化提供新的设计思路和技术支撑。

Strength and ductility/toughness are the main properties of metallic structural materials,while the two properties are always contradictory.Namely,the traditional four strengthening types:solid solute strengthening,nanograin strengthening,dispersive strengthening and work hardening can also strengthen the metallic materials,by the sacrifice of the ductility and toughness.Based on the idea of improving strength and toughness by multiscale hierarchical bionics structure,this work sys-tematically introduces the configuration design,strengthening-toughening and fracture mechanisms of two-scale Ti-TiB w/Ti composites,stainless steel clad plate,multilayer steel,laminated/network/steel and ultrafine fibrous grain steel.The multiscale structure can effectively realize the strengthening and toughening of materials by changing the crack propagation mode,the crack competition mechanism,and the release of residual internal stress.It can provide new design ideas and technical support for the strengthening-toughening of metallic materials.