脉冲次数对电场处理7075铝合金组织和性能的影响
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摘要
采用电导率、维氏硬度、拉伸性能和TEM,研究了脉冲次数对电场处理7075铝合金组织和性能的影响。结果表明,相比处理前,脉冲次数为100时,材料的电导率增加为19.05 MS/m,提高了1.7%,维氏硬度却下降了7.3%;随着脉冲次数的增加,材料的抗拉强度逐渐下降,伸长率则稳步提高,当脉冲次数为100时,材料的抗拉强度下降了6.6%,而伸长率提高了12.1%。经脉冲电场处理后,第二相析出且长大,晶格畸变程度下降,导致导电率升高;晶界沉淀物断续分布,且无沉淀析出带变宽,该合金塑性提高。
The effects of pulse times on the microstructure and properties of 7075 Al alloy treated by electric field were analyzed by electrical conductivity test, vickers hardness test, tensile test and TEM. The results show that compared with that of the alloy before treatment, the electrical conductivity at 100 pulse times raised to 19.05 MS/m and improved by 1.7%,however, the vickers hardness drops by 7.3%. With the increase of pulse times, the tensile strength of the material decreases,but the elongation improves gradually. The tensile strength at 100 pulse times declines by 6.6%, but the elongation enhances by 12.1%. After the pulse electric field treatment, the second phase precipitates and grows, and the lattice distortion decreases,which can result in the increase of electrical conductivity. The grain boundary precipitates distribute intermittently, and the precipitation free zone is widened, and the plasticity of the alloy improves.
The effects of pulse times on the microstructure and properties of 7075 Al alloy treated by electric field were analyzed by electrical conductivity test, vickers hardness test, tensile test and TEM. The results show that compared with that of the alloy before treatment, the electrical conductivity at 100 pulse times raised to 19.05 MS/m and improved by 1.7%,however, the vickers hardness drops by 7.3%. With the increase of pulse times, the tensile strength of the material decreases,but the elongation improves gradually. The tensile strength at 100 pulse times declines by 6.6%, but the elongation enhances by 12.1%. After the pulse electric field treatment, the second phase precipitates and grows, and the lattice distortion decreases,which can result in the increase of electrical conductivity. The grain boundary precipitates distribute intermittently, and the precipitation free zone is widened, and the plasticity of the alloy improves.
引文
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[3]朱义灯.电场固溶处理对铝合金时效成形性的影响[D].南昌:南昌航空大学,2014.
[4]王春华,杨丽娟,尹红霞,等.时效处理对高锌7075铝合金力学性能的影响[J].金属热处理,2018,43(12):148-151.
[5]房洪杰,孙杰,刘慧,等.复合添加Cr、Mn、Ti对7136铝合金组织及力学性能的影响[J].金属热处理,2017,42(4):53-57.
[6]Rao A C,Vasu V,Govindaraju M,et al.Stress corrosion cracking behaviour of 7xxx aluminum alloys:A literature review[J].Transactions of Nonferrous Metals Society of China,2016,26(6):1447-1471.
[7]何正林,高文理,陆政,等.热处理对7A85铝合金组织和性能的影响[J].材料工程,2015,43(8):13-18.
[8]张新明,刘胜胆.航空铝合金及其材料加工[J].中国材料进展,2013,32(1):39-55.
[9]Jia P F,Cao Y H,Geng Y D,et al.Effects of d.c.current on the phase transformation in 7050 alloy during homogenization[J].Materials Characterization,2014,96:21-27.
[10]Shou W,Yi D,Yi R,et al.Influence of electric field on microstructure and mechanical properties of an Al-Cu-Li alloy during ageing[J].Materials&Design,2016,98:79-87.
[11]李宁,张蓉,张利民,等.低压交流电脉冲下Al-7%Si合金晶粒细化机理研究[J].金属学报,2017,53(2):192-200.
[12]Sun K M,Li L,Chen S D,et al.A new approach to control centerline macrosegregation in Al-Mg-Si alloys during twin roll continuous casting[J].Materials Letters,2017,190:205-208.
[13]Zhan L,Ma Z,Zhang J,et al.Stress relaxation ageing behaviour and constitutive modelling of a 2219 aluminium alloy under the effect of an electric pulse[J].Journal of Alloys and Compounds,2016,679:316-323.
[14]Xin S,Tan L,Guangming X.Composition homogenization evolution of twin-roll cast 7075 aluminum alloy using electromagnetic field[J].Rare Metal Materials and Engineering,2015,44(3):581-586.
[15]Li G R,Li Y M,Wang F F,et al.Microstructure and performance of solid TC4 titanium alloy subjected to the high pulsed magnetic field treatment[J].Journal of Alloys and Compounds,2015,644:750-756.
[16]宁爱林,蒋寿生,彭北山.铝合金的力学性能及其电导率[J].轻金属,2005(6):34-36.
[17]康铭,窦志家,刘施洋,等.欠时效时间对LD5挤压棒材的性能、硬度和电导率影响规律研究[J].有色金属加工,2017,46(5):29-31.
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