Effect of Prior Deformation on Tensile and Vibration Fracture Resistance of Friction Stirred 5052 Alloy
Effect of Prior Deformation on Tensile and Vibration Fracture Resistance of Friction Stirred 5052 Alloy
复制标题
预变形对搅拌摩擦5052合金拉伸和振动断裂性能的影响
DOI：
10.2320/matertrans.47.2504
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发表时间：
2006
影响因子：
1.2
通讯作者：
Li
中科院分区：
文献类型：
--
作者：
K. Huang;T. Lui;Li
采用不同的冷轧压下量制备Al-2.5Mg合金，然后进行搅拌摩擦加工（FSP），以研究预先组织变化对搅拌摩擦材料的影响。实验结果表明，FSP试样不仅具有较好的拉伸性能，而且具有较好的抗振动断裂性能，这是由于动态再结晶导致的显微组织细化所致。所有试样的应力-伸长率曲线均呈锯齿状屈服。由FSP引入的较高的晶界可以保持移动的位错足够长的时间，以使Mg原子在它们周围形成气氛。因此，锯齿大小的影响更显着的标本上给予FSP。这可以归因于晶粒细化和由此产生的边界的增加，这是障碍的主要来源。此外，FSP试样的抗振动断裂性能表明，第一阶段的持续时间随着FSP前的预先变形率的增加而减少。同时，在相同的初始挠度幅值（6.5 mm）下，预变形试样具有更好的抗振动断裂性能。基于观察到的显微组织，这可以归因于大量的保留位错缠结引入先前的冷轧，甚至在FSP，这提高了裂纹扩展阻力和降低裂纹扩展速率。实验结果证实，振动断裂阻力可以定量地与裂纹扩展行为对应的裂纹曲折度值相关。[doi：10.2320/matertrans.47.2504]
In this study, Al-2.5Mg alloy was prepared with different cold rolling reductions, and then friction stir processing (FSP) was performed to investigate the effect of prior microstructure variations on friction stirred materials. The experimental results indicate that the FSP specimens not only had better tensile properties but also better vibration fracture resistance, which would be expected from the microstructural refinement which resulted from the phenomenon of dynamic recrystallization. The stress-elongation curves of all specimens showed the serrated yielding. The higher grain boundary introduced by FSP could hold the mobile dislocations long enough to let Mg atoms form atmospheres around them. Consequently, the effect serration magnitude was more significant on the specimens which were given FSP. This can be ascribed to the grain refinement and the resulting increase of the boundaries which is the main source of obstacles. In addition, the vibration fracture resistance of the FSP specimens shows that the duration of stage I decreases with increasing the prior deformation rate before FSP. Meanwhile, the prior deformation samples possessed better vibration fracture resistance under the same initial deflection amplitude (6.5 mm). Based on the observed microstructures, this can be attributed to a large number of retained dislocation tangles introduced by prior cold rolling, even after FSP, which improved the crack propagation resistance and reduced the crack propagation rate. The experimental results confirmed that vibration fracture resistance can be quantitatively correlated with the crack tortuosity value which corresponds to the crack propagation behavior. [doi:10.2320/matertrans.47.2504]