超高塑性镁合金的赝纤维混晶组织形成机理、变形机制与性能调控

镁合金的室温塑性低、成形性差，常规塑性加工方法和强化方式无法解决强度塑性互斥问题，严重限制了其广泛应用。研究表明在合金组织中引入特殊混晶组织能够同时提升合金室温塑性及强度，近年来该理念被应用于镁合金开发设计中，以期通过特殊加工工艺引入混晶组织改善合金性能。本项目针对常规塑性加工方法制备的超高塑性镁合金挤压棒材特殊的赝纤维混晶组织及强度、塑性同时提高的现象，采用原位/准原位等先进表征测试技术与第一性原理计算、晶体塑性有限元模拟相结合的方法，研究超高塑性镁合金赝纤维混晶组织的形成机理及其对塑性变形的影响，阐明超高塑性镁合金室温变形行为，建立基于常规塑性加工方法成形的超高塑性镁合金工艺参数-显微组织-力学性能的一体化调控机制。项目的开展将对丰富镁合金变形理论，开发新型高塑、超高塑性变形镁合金具有重要的参考价值。

The magnesium alloy has low room temperature ductility and poor formability, and the traditional processing technology and the strengthening method cannot avoid strength–ductility trade-off, which severely limits its wide application. Many studies have shown that a special bimodal grain size microstructure in the microstructure can simultaneously improve the room temperature ductility and strength of the alloy. In recent years, the idea of introducing bimodal grain size microstructure to improve the properties of magnesium alloys by special processing technology has been applied to the development and design of magnesium alloys. For its special pseudofiber bimodal microstructure, the in-situ/quasi-in-situ advanced characterization test combined with first-principles calculation and crystal plastic finite element simulation will be used to study the evolution of ultrahigh ductility magnesium alloy pseudofiber microstructure and its influence on plastic deformation, to clarify the ultrahigh ductility deformation mechanism of ultrahigh ductility magnesium alloys, to establish the integrated regulation mechanism of process parameters-microstructure-mechanical properties of ultrahigh ductility magnesium alloys based on conventional process. The development of the project will enrich the theory of magnesium alloy deformation and show significant guidance for developing new high plastic and ultrahigh plastic deformation magnesium alloy.