固相多次合成AZ31-RE耐热变形镁合金及界面结构研究

AZ31-RE heat-resistant wrought magnesium alloy are prepared by solid repeated process. It is easy to solve the inconsistent problem between the acctual meassured value and nominal added value because of the burning loss of RE, and strength the uniformly role of MgxREy phase, Mg17Al12 and oxide phase. In this project, the microstructural evolution, texture, mechanical properties and correlative mechanism of AZ31-RE heat-resistant wrought magnesium alloy prepared by solid repeated process are investigated. According to the theory of dynamics and thermodynamics, microstructure of the interface such as metallurgically combination between magnesium alloy chips, atomic arrangement of the interface, crystal lattice matching and combinative strength between the interface are studied. Strength-toughness mechanism of MgxREy phase, Mg17Al12 phase and oxide phase are attained. Interfacial crack problems of AZ31-RE magnesium alloy are discussed. The interaction integral calculus is derived for the computation of mixed-mode stress intensity factors. The interaction integral calculus method combined with the extended finite element method is used to verify the validation and domain-independence of the interaction integral. Effect of dynamic recrystallization on mechanical properties in the process of solid repeated process and characterization of class I and class II of creep at high temperature are educed. The project provides a theoretical and practical basic for industrialized manufacture of heat-resistant wrought magnesium alloy prepared by solid repeated process.

采用固相多次合成方法合成AZ31-RE耐热变形镁合金，解决了由于稀土元素的烧损，名义上加入的量和实际测的量不一致的问题，充分发挥MgxREy相、Mg17Al12相、氧化相等弥散复合强化作用。本项目研究固相多次合成AZ31-RE耐热变形镁合金组织演变、织构演化和力学性能的变化规律及相关机理；结合热力学和动力学理论，研究镁合金屑间结合机理、界面原子排列、晶格匹配等界面微观结构以及界面结合强度；获得合成镁合金中氧化相、MgxREy相、Mg17Al12相等强韧化机制；探讨合成镁合金中界面裂纹问题，推导求解界面裂纹尖端应力强度因子的相互作用积分，将相互作用积分方法与扩展有限元方法相结合，研究相互作用积分的有效性和区域无关性；揭示固相多次合成过程中动态再结晶对力学性能的影响规律以及高温蠕变的第一阶段和第二阶段特征，为固相合成耐热变形镁合金工业化生产奠定理论及实践基础。

固相多次合成方法是将合金屑、颗粒、纤维先冷压或热压再热挤成形的方法，可以解决普通熔炼方法烧损和氧化，名义上加入的量和实际测的量不一致的问题，合成过程中不需要保护气氛，充分发挥MgxREy相、Mg17Al12相、氧化相等弥散复合强化作用。.本项目制备了成分及组织均匀的AZ31-Ce合金、AZ31-Nd合金、AZ31-Al2O3合金、AZ31-C合金、Mg-Nd-Zn-Zr合金和ZM6-Ce合金，研究屑料尺寸对固相多次合成镁合金位错、动态再结晶及力学性能的影响，固相多次合成中元素之间作用规律。研究了Mg-Ce合金屑、Mg-Nd合金屑、AZ31合金屑、ZM6合金屑、氧化相在合成过程中破碎情况，屑料在固相合成镁合金中的存在形式及其宏观分布规律。研究了固相合成镁合金中稀土相微观形态及分布，稀土相与镁合金基体间界面微结构，分析界面结合机制。.制得了不同工艺参数（挤压次数、挤压温度、挤压比）下合成镁合金试样，研究了挤压次数、挤压温度及挤压比对固相多次合成镁合金位错、动态再结晶组织的影响，研究固相多次合成镁合金动态再结晶规律。研究了不同工艺下固相多次镁合金的性能与组织、结构及稀土相形态分布的关系；结合合金断口形貌，分析了断裂类型及断裂位置，研究界面断裂规律。.与日本东京大学杉山澄雄副教授合作研究“镁合金固相再生及半固态”，探讨合金屑结合机理、界面原子排列、晶格匹配等界面结合及断裂行为。本项目为固相多次合成耐热变形镁合金工业化生产奠定理论及实践基础。.在国内、国际学术刊物发表论文6篇，其中4篇SCI收录，2篇EI收录；授权中国发明专利4项，申请中国发明专利1项；培养硕士研究生2名，协助培养博士研究生1名。