摘要
The effects of aging treatments on the tensile properties and compressive behavior of a thin-walled 6005 aluminum alloy tube were studied.Samples after three natural aging(NA)conditions were subsequently aged at 180℃ for 0.5−12.0 h artificial aging(AA).Tensile and compressive tests were performed after AA.The results show that for samples with the same NA,the longer the AA time is,the higher the strengths alloy owns,and at the same time the material shows a much lower elongation and faster process from plastic deformation to fracture.However,with NA prolonging,the alloy exhibits much better plastic deformation ability after AA,though its strength is decreased.The major cause of strength and plasticity variation induced by changing NA time is that the size of the main strengtheningβ''precipitates is larger and the density is lower.This character is evaluated by the strain hardening exponent n.Compressive results show that the optimum energy absorption characteristics can be acquired at a moderate n(14<n<17).Large n(n≥18)results in the fracture of tube during axial compression while low n(n≤13)causes lower energy absorption.
本文研究了不同时效处理对6005铝合金薄壁管拉伸和压缩性能的影响。薄壁管样品经过三种不同自然时效后,在180℃下人工时效0.5−12.0 h,随后进行拉伸和压缩试验。结果表明:在相同自然时效条件下,人工时效时间越长,合金强度越高,同时其伸长率越低,且从塑性变形到开裂的过程越快;而随着自然时效时间的延长,合金在人工时效后的强度降低,但其具有更好的塑性变形能力。由自然时效变化引起的合金强度和塑性的改变,主要是因为随着自然时效时间的延长,主要的强化相β''相的尺寸更大、密度更低。此种特征可由应变硬化指数n进行表征。同时,压缩试验结果表明,当14<n<17时,薄壁管的吸能最优;当n≥18时,压缩过程中薄壁管发生开裂;而当n≤14时,薄壁管的吸能较少。
作者
ZHANG Long
LI Ke
HE Hong
LI Luo-xing
张龙;李克;何洪;李落星(State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,College of Mechanical and Vehicle Engineering,Hunan University,Changsha 410082,China;AECC South Industry Co.,Ltd.,Zhuzhou 412002,China)
基金
Project(2019JJ50054)supported by the Natural Science Foundation of Hunan Province,China
Projects(51975201,U1664252)supported by the National Natural Science Foundation of China。
