Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第23卷    第5期    总第170期    2013年5月

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文章编号:1004-0609(2013)05-1182-07
低温球磨制备超高强度块体纳米晶纯铝
李炯利,厉沙沙,樊振中,李 伟,熊艳才

(北京航空材料研究院,北京 100095)

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。

 

关键字: 纳米晶;纯铝;低温球磨;微观组织;力学性能;强化机理

Preparation of super high strength bulk nanocrystalline Al by cryomilling
LI Jiong-li, LI Sha-sha, FAN Zhen-zhong, LI Wei, XIONG Yan-cai

Beijing Institute of Aeronautical Materials , Beijing 100095, China

Abstract:The combination of three processing routes of cryomilling, hot isotropic pressing (HIP) and hot extrusion was employed for the fabrication of the bulk nanocrystalline Al. The microstructure and thermal stability of the bulk nanocrystalline Al 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 Al were also measured. Besides, the tensile fracture surface of the bulk nanocrystalline Al 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 Al were quantitatively estimated by Hall-Petch, Orowan and Taylor equations, separately. The results demonstrate that the average grain size of the bulk nanocrystalline Al is approximately 300 nm. The density and microhardness of the bulk nanocrystalline Al 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 Al can be mainly attributed to the grain-size effect and Orowan strengthening.

 

Key words: nanocrystalline; aluminum; cryomilling; microstructure; mechanical properties; strengthening mechanism

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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