摘要
The mechanical properties and microstructure of Al-Cu-Li alloy sheets subjected to cryorolling(-100 ° C,-190 ℃) or hot rolling(400 ℃) and subsequent aging at 160 ℃ for different times were investigated. The dynamic precipitation and dislocation characterizations were examined via transmission electron microscopy and X-ray diffraction. The grain morphologies and the fracture-surface morphologies were studied via optical microscopy and scanning electron microscopy. Samples subjected to cryorolling followed by aging exhibited relatively high dislocation densities and a large number of precipitates compared with hot-rolled samples. The samples cryorolled at-190 ℃ and then aged for 15 h presented the highest ultimate tensile strength(586 MPa), while the alloy processed via hot rolling followed by 10 h aging exhibited the highest uniform elongation rate(11.5%). The size of precipitates increased with the aging time, which has significant effects on the interaction mechanism between dislocations and precipitates. Bowing is the main interaction method between the deformation-induced dislocations and coarsened precipitates during tensile tests, leading to the decline of the mechanical properties of the alloy during overaging. These interesting findings can provide significant insights into the development of materials possessing both excellent strength and high ductility.
研究了深冷轧制(-100℃,-190℃)和热轧(400℃)并随后在160℃时效不同时间的Al-Cu-Li合金带材的力学性能和显微组织。通过透射电子显微镜和X射线衍射检查了动态析出和位错特征。通过超景深显微镜和扫描电子显微镜研究了微观组织和断口表面形貌。与热轧样品相比,经过深冷轧制和时效的样品表现出较高的位错密度和大量的析出物。在-190℃深冷轧制后时效15 h的样品表现出最高的极限抗拉强度(586 MPa),而通过热轧随后5 h时效处理的合金则表现出最高的均匀延展性(11.5%)。析出物的尺寸随着时效时间的增加而增加,这对位错与析出物之间的相互作用机理具有重要影响。过时效时,析出物尺寸比较粗大,拉伸变形过程中位错会绕过析出物进行运动,进而力学性能下降。
作者
WANG Lin
BHATTA Laxman
XIONG Han-qing
LI Chang
CUI Xiao-hui
KONG Charlie
YU Hai-liang
王琳;BHATTA Laxman;熊汉青;李畅;崔晓辉;KONG Charlie;喻海良(State Key Laboratory of High Performance Complex Manufacturing,Central South University,Changsha 410083,China;College of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;Light Alloys Research Institute,Central South University,Changsha 410083,China;Electron Microscope Unit,University of New SouthWales,Sydney,NSW 2052,Australia)
基金
Project(2019YFB2006500) supported by the National Key Research and Development Program,China
Project(51674303) supported by the National Natural Science Foundation of China
Project(2020GK2032) supported by Hunan High-tech Industry Science and Technology Innovation Leading Plan,China
Project (2018RS3015) supported by the Huxiang High-level Talent Gathering Project of Hunan Province,China
Project(2017YFA0700700) supported by the Ministry of Science&Technology of China
Project(2019CX006) supported by Innovation Driven Program of Central South University,China。
