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Journal of Materials Science & Technology 2023年第15期146卷 240-251页

作者： Yan Zou Lingfei Cao Xiaodong Wu Songbai Tang Mingxing Guo Engineering Research Center for Waste Oil Recovery Technology and Equipment Ministry of EducationChongqing Technology and Business UniversityChongqing 400067China International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Shenyang National Laboratory for Materials Science Chongqing UniversityChongqing 400044China State Key Laboratory for Advanced Metals and Materials University of Science and TechnologyBeijing 100083China

Al-Zn-Mg-Cu alloys with different major strengthening precipitates are subjected to a novel combinatorial pre-treatment,including natural ageing and *** evolution of hardness and microstructure during the combinatorial pre-treatment and subsequent artificial ageing has been *** results reveal that the growth rate of hardness in alloy B(Zn/Mg=10.0)is much higher than that of alloy A(Zn/Mg=1.5)due to the fast precipitation kinetics ofηphase compared with T *** GP I zones and dislocations introduced by the combinatorial pre-treatment can act as heterogeneous nucleation sites for precipitation,resulting in more precipitates and higher hardness than pre-stretched alloys A and *** distribute uniformly in combinatorial pre-treated alloys owing to the existence of GP I zones and dislocations,which promote the precipitation and refine the precipitate ***,these alloys with distinct pre-stretching(2%–10%)show similar precipitation behavior and peak hardness,and it indicates that the dislocation-induced precipitation will not be affected by the density of dislocations when plenty of GP I zones pre-exist.

关键词： Combinatorial pre-treatment Zn/Mg ratio ageing behavior Microstructure evolution

Effect of Li addition on mechanical properties and ageing precipitation behavior of extruded Al-3.0 Mg-0.5 Si alloy

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Journal of Central South University 2021年第9期28卷 2636-2646页

作者： YANG Xiao-kun XIONG Bai-qing LI Xi-wu YAN Li-zhen LI Zhi-hui ZHANG Yong-an LI Ya-nan WEN Kai LIU Hong-wei State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.Ltd.Beijing 100088China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China

The effect of Li(2.0 wt%)addition on mechanical properties and ageing precipitation behavior of Al-3.0 Mg 0.5 Si was investigated by tensile test,dynamic elasticity modulus test,scanning electron microscopy(SEM),transmission electron microscopy(TEM)and high-resolution transmission electron microscopy(HRTEM)*** results show that the tensile strength of the Li-containing alloy can be significantly improved;however,the ductility is sharply decreased and the fracture mechanism changes from ductile fracture to intergranular *** elasticity modulus of the Li-containing alloy increases by 11.6%compared with the base *** microstructure observation shows that the Li addition can absolutely change the precipitation behavior of the base alloy,andδ′-Al_(3)Li phase becomes the main ***,β′′-Mg_(2)Si andδ′-Al_(3)Li dual phases precipitation can be visibly observed at 170℃ ageing for 100 h,although the quantity ofδ′-Al_(3)Li phase is more thanβ′′-Mg_(2)Si *** width of the precipitate-free zone(PFZ)of the Li-containing alloy is much wider at the over-ageing state than the base alloy,which has a negative impact on the ductile and results in the decrease of elongation.

关键词： Al-3.0 Mg-0.5 Si alloy Li addition microstructure ageing behavior mechanical properties dynamic elasticity modulus

Altered age-hardening behavior in the ultrafine-grained surface layer of Mg-Zn-Y-Ce-Zr alloy processed by sliding friction treatment

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Journal of Materials Science & Technology 2021年第19期78卷 20-29页

作者： Chunquan Liu Xianhua Chen Yuan Yuan Wei Zhang Yusheng Zhang Fusheng Pan International Joint Laboratory for Light Alloys(MOE) College of Materials Science and EngineeringChongqing UniversityChongqing400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing400045China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Northwest Institute for Nonferrous Metal Research Xi'an710016China

To gain insight into the ageing behavior of ultrafine grain(UFG)structure,the precipitation phenomena and microstructural evolutions of Mg-6 Zn-1 Y-0.4 Ce-0.5 Zr(wt.%)alloy processed by sliding friction treatment(SFT)were systematically studied using hardness texting,transmission electron microscopy(TEM)equipped with high-angle annular dark-field scanning(HADDF-STEM),X-ray diffraction(XRD)and XRD line broadening *** microhardness of the SFT-processed(SFTed)sample initially decreases from 109.6 HV to 104.8 HV at ageing for 8 h,and then increases to the peak-ageing point of 115.4 HV at16 ***,it enters the over-aged *** un-SFTed sample,as the counterpart,follows a regular ageing behavior that increases from 89.9 HV to 99.6 HV when ageing for 12 h,and then drops.A multi-mechanistic model is established to describe the strengthening due to grain refinement,dislocation accumulation,precipitation *** analysis reveals that the temperature sensitive UFG structure has an obvious grain coarsening effect,which arouses the soft phenomenon in the early ageing *** precipitation hardening provides an excellent hardness enhancement for overcoming the negative influence and helping to reach the peak-aged *** our microstructural observations,a lot of equilibrium ultrafine Mg Zn2 precipitates precipitate along dislocations because defects can provide the favorable conditions for the migration and segregation of solute atoms.

关键词： ageing behavior Ultrafine-crystalline grain Nano precipitates Sliding friction treatment

Tailoring phase fractions of T'and η' phases in dual-phase strengthened Al−Zn−Mg−Cu alloy via ageing treatment

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Transactions of Nonferrous Metals Society of China 2022年第10期32卷 3182-3196页

作者： Yan ZOU Xiao-dong WU Song-bai TANG Kai ZHAO Ling-fei CAO International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Shenyang National Laboratory for Materials Science Chongqing UniversityChongqing 400044China

Hardness tests and transmission electron microscopy were used to investigate the strategy of tailoring the phase fraction of precipitates in an Al-Zn-Mg-Cu alloy strengthened by T’ and η’ phases. Different phase fractions of T’ and η’ phases are presented in samples subjected to either single or two stages of ageing treatments at 120 and 150 ℃.For both types of ageing, the precipitation of η’ phase is found to be promoted by ageing at lower temperature and its phase fraction increases with prolonging ageing time at 120 ℃;whereas the phase fractions of T’ and η’ phases almost remain constant during ageing at 150 ℃. Besides, the strain fields produced by T’ and η’ phases were analyzed by using the geometric phase analysis technique, and on a macroscale the contributions of T’ and η’ phases to precipitation strengthening have been quantitatively predicted by combining the size, phase fraction and number density of precipitates.

关键词： Al−Zn−Mg−Cu alloy ageing behavior microstructure dual-phase strengthening

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Aging behavior of As-Extruded Ti Particles Reinforced VW94 Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 401-406页

作者： Dongmei Pu Xianhua Chen Jingfeng Wang Jun Tan Jianbo Li Hong Yang Bo Feng Kaihong Zheng Fusheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400045China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China

The ageing behavior of as-extruded Ti_(P)/VW94 composites was *** peak hardness of the composites increases compared to the matrix alloy and the 5%Ti_(P)/VW94 composite presents the highest peak hardness of 148.7 HV after aging for about 50 ***,the hardness increments first decrease and then slightly increase with increasing Ti particle content due to the introduction of high-density dislocations by Ti particles.

关键词： Magnesium matrix composites Ti particles ageing behavior Hardness

Corrosion behavior of 2024 Al-Cu-Mg alloy of various tempers

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Transactions of Nonferrous Metals Society of China 2013年第11期23卷 3215-3227页

作者： K.S.GHOSH Md.HILAL Sagnik BOSE Department of Metallurgical and Materials Engineering National Institute of TechnologyDurgapur-713 209 India

Corrosion behavior of 2024 Al-Cu-Mg alloy of different tempers was assessed by potentiodynamic polarization studies in 3.5% NaCl solution, 3.5% NaCI＋I.0% H2O2 solution and 3.5% NaCl solution at pH 12. Polarization curves showed shifting of corrosion potential （φPcor） towards more negative potential with increasing ageing time and shifting of φcorr in the positive direction with the addition of H2O2 in NaCl solution. Polarization curves in 3.5% NaCl solution at pH 12 exhibited distinct passivity phenomenon. Optical micrographs of the corroded surfaces showed general corrosion, extensive pitting and intergranular corrosion as well. Cyclic potentiodynamic polarization curves exhibited wide hysteresis loop and the mode of corrosion attack confirmed that the alloy states are susceptible to pit growth damage. Attempts were made to explain the observed corrosion behavior of the alloy of various tempers in different electrolytes with the help of microstructural features.

关键词： 2024 Al-Cu-Mg alloy ageing behavior electrochemical polarization passivity pitting potential