| 铝锂合金单、多晶体的形变行为 | |
| 刘武 | |
| Subtype | 硕士 |
| Thesis Advisor | 王中光 |
| 1992 | |
| Degree Grantor | 中国科学院金属研究所 |
| Place of Conferral | 中国科学院金属研究所 |
| Abstract | 为了更好地了解Al-Li合金的形变断裂机理，本文系统地研究了二元Al-Li合金多晶体、单晶体在不同时效状态下，不同实验温度下的拉伸行为，以及常温下Al-Li单晶体的疲劳性能。对其滑移机制，断裂方式以及形变局部化的条件进行了分析。实验结果表明，二元Al-Li多晶体不一定具有较常温好的低温强度。延伸率总是随着σ_b 与σ_s的差距的增加而增加。拉伸过程中，普遍存在着P-L效应。由低温到室温，在150K时，断裂方式由沿晶正断转变为剪切断裂。Al-Li单晶体的疲劳实验表明，峰值时效材料发生了平面滑移，而对于过时效材料则为波纹滑移，在6.0 * 10~(-4) < γ_P < 4.0 * 10~(-3)范围内，饱和应力幅十分依赖于γ_(PL)值。分析表明，具有LI_2型的共格有序强化相δ'粒子与位错的交互作用是造成不同时效状态下以及不同实验温度下性能发生转变的主要原因。晶界十分影响材料的强度和断裂方式，平面滑移不是产生Al-Li合金低延性断裂的直接原因。材料的总体性能由晶界强度、δ'相粒子强度和基体强化作用三个部分所决定。 |
| Other Abstract | In order to clarify the deformation and fracture mechanisms of Al-Li alloy the tensile behaviours of binary Al-Li polycrystals and single crystals have been studied at different aged conditions and different experiment temperature in this paper. The fatigue behaviours also have been studied on Al-Li single crystals at ambient temperature. The slip mechanisms of dislocation, Fracture style and occurance of shear localization have been analyzed in the present study. The experiment data are shown that binary Al-Li polycrystals have not always good strnegth at lower temperature. The increment of elongation is followed by the raise of (σ_b-σ_s). In tensile process, P-L effection is always existed in every aged materials. The Fracture style changes from intergranular fracture to shear Fracture at 150K, when experiment temperature rise from 77K to 290K. In the experiment of fatigue in Al-Li single crystals, planar slip line has been found in peak-aged condition, but appears wave slip in over-aged condition. Saturation stress amplitude is very depondent on plastic strain amplitude at the range of 6.0 * 10~(-4) < δ_P < 4.0 * 10~(-3). It is shown that the interaction between dislocation and δ' precipitate phase particle, which has LI_2 style structure, is the major reason for different characters at different aged condition and temperature. The grain boundary has obvious influence on the strength and fracture style. The planar slip is not the directive reason for lower toughness on this mateiral. The strength of binary Al-Li alloy is dependent on boudnary, δ' particles and matrix. |
| Pages | 69 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/17546 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | 刘武. 铝锂合金单、多晶体的形变行为[D]. 中国科学院金属研究所. 中国科学院金属研究所,1992. |
| Files in This Item: | There are no files associated with this item. | |||||
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.
Edit Comment