摘要
采用低温球磨、热等静压和挤压等工艺制备块体纳米晶纯铝。分别采用透射电镜(TEM)和差热分析(DSC)对块体纳米晶纯铝的微观组织和热稳定性进行研究,并对所制备的块体纳米晶纯铝的化学成分、密度、硬度和拉伸性能进行测定,借助扫描电镜(SEM)对块体纳米晶纯铝的拉伸断口进行观察。同时,分别依据Hall-Petch公式、Orowan机制和Taylor公式定量估算细晶强化、弥散强化和位错强化对块体纳米晶纯铝屈服强度的独立贡献。结果表明:所制备的块体纳米晶纯铝的平均晶粒尺寸约为300 nm,密度为2.692 g/cm3,显微硬度为109.15HV;块体纳米晶纯铝的屈服强度和抗拉强度分别达270 MPa和379 MPa,伸长率为3.2%;块体纳米晶纯铝的高强度主要可归因于细晶强化和弥散强化。
The combination of three processing routes of cryomilling, hot isotropic pressing （HIP） and hot extrusion was employed for the fabrication of the bulk nanocrystalline A1. The microstructure and thermal stability of the bulk nanocrystalline AI were studied by transmission electron microscopy （TEM） and differential scanning calorimetry （DSC）, respectively. The chemical composition, density, microhardness and tensile property of the bulk nanocrystalline AI were also measured. Besides, the tensile fracture surface of the bulk nanocrystalline A1 was observed by scanning electron microscopy （SEM）. Furthermore, the contributions of grain-size effect, Orowan strengthening and dislocation strengthening to the yield strength of the bulk nanocrystalline A1 were quantitatively estimated by Hall-Petch, Orowan and Taylor equations, separately. The results demonstrate that the average grain size of the bulk nanoerystalline AI is approximately 300 nm. The density and mierohardness of the bulk nanocrystalline A1 are 2.692 g/cm3 and 109.15HV, respectively. The resulted sample exhibits super high yield strength of 270 MPa and ultimate strength of 379 MPa with an elongation of 3.2%. The enhanced strength of the bulk nanocrystalline AI can be mainly attributed to the grain-size effect and Orowan strengthening.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2013年第5期1182-1188,共7页
The Chinese Journal of Nonferrous Metals
基金
北京航空材料研究院创新基金资助项目(KF35090202)
关键词
纳米晶
纯铝
低温球磨
微观组织
力学性能
强化机理
nanocrystalline
aluminum
cryomilling
microstructure
mechanical properties
strengthening mechanism
