基本信息
项目批准号：51404180
申请代码：E0414
项目名称：搅拌摩擦加工超细晶镁合金塑韧化机制研究
项目负责人：王文(wén)
依托单位：西安建筑科(kē)技大學(xué)
研究期限：2015-01-01 至 2017-12-31
资助经费：25.0（万元）

项目摘要
中文(wén)摘要：
细晶强化是提高镁合金强度的有(yǒu)效方法，但由于超细晶内部存储位错的能(néng)力较低，造成塑性变形过程中的应变硬化缺失，从而导致超细晶室温塑韧性较差。晶界特征和晶粒取向是决定超细晶镁合金室温塑韧性的关键因素。本项目先以固溶體(tǐ)镁合金為(wèi)对象，采用(yòng)搅拌摩擦加工（FSP）技术制备出具有(yǒu)不同晶界特征和晶粒取向的超细晶镁合金。采用(yòng)TEM、SEM、EBSD、XRD等技术对超细晶晶界特征、晶粒取向、位错组态等进行表征，通过实验手段分(fēn)离晶界特征、晶粒取向对塑韧性的单独作用(yòng)机制。再以时效控制可(kě)热处理(lǐ)强化镁合金中的第二相分(fēn)布，分(fēn)析第二相对超细晶镁合金塑韧性作用(yòng)规律。通过这些深入研究，揭示超细晶镁合金应变硬化与延伸率的本构量化关系，阐明高角度晶界和晶粒取向对超细晶镁合金塑韧化作用(yòng)机制，探讨通过调控微观结构和外界变形条件提高超细晶镁合金塑韧性的方法，从而為(wèi)超细晶镁合金材料的增韧结构优化设计提供实验依据和理(lǐ)论指导。
英文(wén)摘要：
Grain refinement is an effective method for improving the strength of magnesium alloy. However, lower strain hardening capacity of the ultra-fine grained (UFG) material during plastic deformation process, due to lower storage capacity for intragranular dislocation, results in lower plasticity and toughness at room temperature. The characteristic of grain boundary and grain orientation are two key factors in room temperature plasticity and toughness of the UFG magnesium alloy. In this project, firstly, friction stir processing (FSP) will be used to fabricate the UFG solid solution magnesium alloy with different grain boundary characteristic and grain orientation. Microstructure characteristic of the UFG, such as grain boundary, grain orientation, and dislocation configuration, will be investigated using TEM, SEM, EBSD and XRD et al.. Meanwhile, the effect of grain boundary and grain orientation on the plasticizing and toughening mechanism will be investigated separately. Furthermore, the distribution of the second phase in heat-treatable strengthening magnesium alloy will be changed by ageing treatment, and then the effect of the second phase on the plasticity and toughness of the UFG magnesium alloy will be studied. Based on the above intensive investigation, quantifiable constitutive relation between the strain hardening and elongation will be revealed, and the effect of high-angle grain boundary and grain orientation of the UFG magnesium alloy on the plasticizing and toughening mechanism will be further interpreted. Meanwhile, new methods of improving plasticity and toughness of the UFG magnesium alloy via adjusting the microstructure and external deformation condition will also be discussed. The results of this project will provide experimental data and theoretical basis for the toughened optimal design on the microstructure of the UFG magnesium alloy.
                                                                                                                                                                             ——来自https://kd.nsfc.gov.cn/