超高强Al-Gd-Ni-Co纳米结构铝合金的增韧机制研究

开发兼具高强度和良好拉伸塑性的纳米结构铝合金，将对促进高性能铝合金在航空航天、轨道交通和汽车等领域的应用产生积极作用，但是纳米结构铝合金的塑性和增韧机制还有待于进一步提高和阐明。申请者在前期研究中制备出了超高强度的Al-Gd-Ni-Co纳米结构铝合金，压缩屈服强度达到了1700 MPa。本项目拟以超高强Al-Gd-Ni-Co纳米结构铝合金为对象，通过调控基体铝的比例和导入韧性粗晶相获得双尺度结构两种途径，来提高超高强度纳米结构铝合金的韧性，制备具有高强度（1GPa）和良好拉伸塑性的铝合金，重点从原子尺度揭示高应力下纳米化合物中裂纹的萌生和扩展机制，并阐明拉伸条件下基体铝和韧性粗晶相对纳米化合物的限制效应。本项目可为研制高性能铝合金材料提供技术指导，促进高性能铝合金的应用，同时丰富铝合金在高应力条件下的强韧化理论。

The development of high performance nanostructured aluminum alloys with both high strength and large tensile plasticity will promote their application in aerospace, rail transit, car, etc. However, the ductility of nanostructured aluminum alloys needs to be further improved and the toughening mechanism is still unclear. We have recently developed a super-high strength nanostructured Al-Gd-Ni-Co alloy with compressive yield strength as high as 1700 MPa. In this research project, in order to produce high strength (1GPa) aluminum alloy with large tensile plasticity, two methods will be used to improve the ductility by developing more volume fraction of ductile phases and adding coarse grained ductile phase in the developed super-high strength Al-Gd-Ni-Co alloy. This research project will focus on the micro crack origination in the nanoscale intermetallics and crack propagation under high stress, as well as the confined effect of the ductile phases on the nanoscale intermetallics under tensile stress. The outcome of this research project is expected to have technique guidance in the field of high performance aluminum alloys which enhances their applications, and potentially leads to improvement in understanding the strengthening and toughening mechanisms in high performance aluminum alloys.