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Rare Metals 2023年第6期42卷 2057-2067页

作者： Sen Lin yun-lai deng Hua-Qiang Lin Ling-Ying Ye Zhen Zhang Hua Ji Xin-Ming Zhang School of Materials Science and Engineering Central South UniversityChangsha410083China Light Alloy Research Institute Central South UniversityChangsha410083China Guangxi Liuzhou Yinhai Aluminum Co. LtdLiuzhou545006China National Engineering Research Center for High-Speed EMU CRRC Qingdao Sifang Co.LtdQingdao266000China

Microstructure,mechanical properties and stress corrosion behavior of friction stir welded(FSWed) AlMg-Si alloy were *** average grain sizes of shoulder-affected zone(SAZ),nugget zone(NZ),heat-affected zone(HAZ) and base material(BM) are 6.03,4.80,168.30 and 127.24 μm,*** thermo-mechanically affected zone(TMAZ),which is generated on the edge position between HAZ and weld nugget zone,has a narrow width of 400 μ*** ultimate tensile strength(UTS) of FSWed joint is 232.20 MPa,about 91.04% with respect to that of base material of 255.06 MPa,and the joint fracture occurs at HAZ on advancing side(AS).The FSWed joint is more susceptive to stress corrosion cracking(SCC) than base material,and the SCC susceptibility increases with the rise in *** residual UTS of FSWed joints in constant loaded tests at the load levels of90,105 and 120 MPa is 89.97%,67.50% and 54.75% of the UST of FSWed joint in air,*** increase of the load in constant loaded tests and four-point beambent tests accelerates the SCC of FSWed joints.

关键词： EBSD Slow strain rate test Stress corrosion cracking Al-Mg-Si alloy Friction stir welding

Calculation and experimental study on heating temperature field of super-high strength aluminum alloy thick plate

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Transactions of Nonferrous Metals Society of China 2017年第11期27卷 2415-2422页

作者： Shi-tong FAN yun-lai deng Jin ZHANG Xiao-bin GUO School of Materials Science and Engineering Central South University Changsha 410083 China State Key Laboratory of High Performance and Complex Manufacturing Central South University Changsha 410083 China Light Alloy Research Institute Central South University Changsha 410083 China

Stepped heating treatment has been applied to aluminum alloy thick plate to improve the mechanical performance and corrosion *** temperature control of the plate is the difficulty in engineering *** heating process,the calculation of surface heat transfer coefficient and the accurate temperature control method were studied based on measured heating temperature for the large-size thick *** results show that,the temperature difference between the surface and center of the thick plate is *** on the temperature uniformity,the surface heat transfer coefficient was calculated,and it is constant below300°C,but grows greatly over300°***,a lumped parameter method(LPM)was developed to predict the plate temperature.A stepped solution treatment was designed by using LPM,and verified by finite element method(FEM)and *** curves calculated by LPM and FEM agree well with the experimental data,and the LPM is more convenient in engineering application.

关键词： lumped parameter method surface heat transfer coefficient temperature field aluminum alloy thick plate

Deformation characteristics and strain-compensated constitutive equation for AA5083 aluminum alloy under hot compression

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Transactions of Nonferrous Metals Society of China 2019年第11期29卷 2252-2261页

作者： Qing-song DAI yun-lai deng Jian-guo TANG Yu WANG School of Materials Science and Engineering Central South UniversityChangsha 410083China Guangxi Liuzhou Yinhai Aluminum Co. Ltd.Liuzhou 545006China

The hot deformation behavior of AA5083 aluminum alloy was studied using isothermal compression tests with a Gleeble 3500 thermal simulator at strain rate of 0.0110 s 1 and at temperature of 300500°*** experimental results indicate that dynamic recrystallization(DRX)tends to occur at high strain rates and temperatures,and therefore the flow stress is *** predict the flow behavior under different deformation conditions,a strain-compensated constitutive equation based on Arrhenius-type equation and Zener Hollomon parameters was *** flow stresses obtained from the constitutive equation are consistent with the experimental *** average absolute relative error is only 4.52%over the entire experimental range,indicating that the proposed constitutive equation exhibits high prediction precision for the hot deformation behavior of AA5083 aluminum alloy.

关键词： hot deformation AA5083 dynamic recrystallization constitutive equation

Quenching sensitivity and heterogeneous precipitation behavior of AA7136 alloy

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Transactions of Nonferrous Metals Society of China 2021年第11期31卷 3356-3369页

作者： Zhi-min MA Yong ZHANG Sheng-dan LIU yun-lai deng Xin-ming ZHANG School of Materials Science and Engineering Central South UniversityChangsha 410083China Baotou Vocational&Technical College Baotou 014030China Key Laboratory of Non-ferrous Metals Materials Science and Engineering Ministry of EducationCentral South UniversityChangsha 410083China

The quenching sensitivity of AA7136 alloy was investigated by time−temperature−property(TTP)diagrams,and the heterogeneous precipitation behavior during isothermal holding was investigated using scanning electron microscopy,scanning transmission electron microscopy and high resolution transmission electron *** on 99.5%TTP diagram,the nose temperature is determined to be about 346℃ with the transformation time of about 0.245 *** precipitation ofη(MgZn_(2)),T(Al_(2)Zn_(3)Mg_(3)),S(Al_(2)CuMg)or Cu−Zn-rich Y phases can be found depending on isothermal holding temperature and time,and it is described in a time−temperature−precipitation *** size and area fraction of isothermal holding induced phase particles increase,which results in the decrease of hardness of samples after *** quantitative contribution to loss of hardness by grain boundaries/subgrain boundaries and dispersoids in the matrix is discussed based on the amount of heterogeneous precipitation related to them.

关键词： AA7136 alloy quenching sensitivity time−temperature−property diagrams heterogeneous precipitation

Influence of sub-grain boundaries on quenching process of an Al-Zn-Mg-Cu alloy

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Transactions of Nonferrous Metals Society of China 2014年第7期24卷 2117-2121页

作者：姜柯达陈龙张云崖邓运来中南大学材料科学与工程学院长沙410083 中南大学高性能复杂制造国家重点实验室长沙410083

The effects of sub-grain boundaries on the quenching sensitivity and the precipitation behavior in Al-7.01Zn-1.26Mg- 1.43Cu alloy were investigated by an end-quenching test. Specimens were solution treated at 440 ℃ and 480 ℃ to get different recrystallization fractions, respectively. The results show that the maximum hardness value of the Al-Zn-Mg-Cu alloy can be improved by the sub-grain boundaries, but the depth of age-hardening layer decreases significantly. The precipitation temperature and the activation energy are reduced by the changes of surface energy, which is induced by sub-grain boundaries. So, the precipitation process from η phase to η phase becomes much easier. In this way, an increase in the number of sub-grain boundaries promotes the precipitation of MgZn2 particles, especially η＇-MgZn2.

关键词： Al-Zn-Mg-Cu alloy recrystallization grain boundary precipitation quenching

Effect of three-step homogenization on microstructure and properties of 7N01 aluminum alloys

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Transactions of Nonferrous Metals Society of China 2018年第5期28卷 829-838页

作者： Hua-qiang LIN Ling-ying YE Lin SUN Tao XIAO Sheng-dan LIU yun-lai deng Xin-ming ZHANG National Engineering Research Center for High-Speed EMU CRRC Qingdao Sifang Co. Ltd. Qingdao 266000 China School of Materials Science and Engineering Central South University Changsha 410083 China Light Alloy Research Institute Central South University Changsha 410083 China

The effect of different homogenization treatments on the microstructure and properties of the 7N01 aluminum alloy was investigated using hardness measurements, electrical conductivity measurements, tensile and slow strain rate tests, electron probe microanalysis, optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results revealed that three-step homogenization improved the uniformity of Zr distribution by eliminating segregation of the main alloying elements. During the second homogenization step at 350 °C for 10 h, coarse and strip-like equilibrium η phases formed which assisted the nucleation of Al3Zr dispersoids and reduced the width of the precipitate-free zone of A13Zr dispersoids. As a result, coarse recrystallization was greatly reduced after homogenization at 200 °C, 2 h ＋ 350 °C, 10 h ＋ 470 °C, 12 h, which contributed to improving the overall properties of the 7N01 aluminum alloys.

关键词： 7N01 aluminum alloy three-step homogenization microstzucture mechanical properties stress corrosion cracking

Precipitation orientation effect of 2124 aluminum alloy in creep aging

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Transactions of Nonferrous Metals Society of China 2014年第7期24卷 2067-2071页

作者：胥福顺张劲邓运来张新明云南冶金集团股份有限公司昆明650502 中南大学材料科学与工程学院长沙410083 中南大学高性能复杂制造国家重点实验室长沙410083

The precipitation behaviors of 2124 aluminum alloy under the conditions of artificial aging （AA）, creep aging （CA） and creep aging with pre-deformation （PCA） were investigated by means of mechanical property and microstructure. The results show that the mechanical properties of CA treated sample decrease significantly compared with AA treated sample. The yield strength of the CA treated sample falls by 14%, the tensile strength falls by 6.2%, and the elongation falls by 21%. Nevertheless, the mechanical properties of PCA sample are improved obviously, close to the AA treated sample. Moreover, the generation and control mechanisms of the precipitation orientation effect in 2124 aluminum alloy were studied. It is deduced that the key mechanism lies in the effect of dislocation.

关键词： 2124 aluminum alloy creep aging orientation effect dislocation

Modification of Mg_2Si in Mg-Si alloys with neodymium

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Transactions of Nonferrous Metals Society of China 2013年第11期23卷 3161-3166页

作者：胡继龙唐昌平张新明邓运来中南大学材料科学与工程学院长沙410083 中南大学有色金属材料科学与工程教育部重点实验室长沙410083 北汽股份汽车研究院北京101300

The modification effect of neodymium （Nd） on Mg2Si in the hypereutectic Mg-3%Si （mass fraction） alloy was investigated by optical microcopy, scanning electron microscopy and X-ray diffraction. The results indicate that the morphology of the primary Mg2Si transforms from coarse dendrite into fine polygon with increasing Nd content. The average size of the primary Mg2Si significantly decreases to about 10 ~ma with increasing Nd content up to 1.0%, and then becomes coarser again. The modification and refinement of the primary Mg2Si are mainly attributed to the poisoning effect. The NdMg2 phase in the primary Mg2Si transforms into NdSi and NdSi2 compounds as the Nd content exceeds 3.0%. Therefore, it is reasonable to conclude that the proper Nd （1.0%） addition can effectively modify and refine the primary Mg2Si.

关键词： Mg-Si alloy modification Mg2Si Nd

Microstructure and mechanical properties of Al−Mg−Si alloy U-shaped profile

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Transactions of Nonferrous Metals Society of China 2020年第11期30卷 2915-2926页

作者： Xiang-dong WANG Xiong LIU Hao DING Su-rong YAN Zi-hua XIE Bai-qing PAN Yong-hong LI Qing-lin PAN yun-lai deng Wei-yi WANG Manufacturing Center Zhuzhou CRRC Times Electric Co.Ltd.Zhuzhou 412001China School of Materials Science and Engineering Central South UniversityChangsha 410083China

To get a full understanding of hot extrusion,solid solution treatment and aging process on the Al−0.56Mg−0.63Si alloy,the microstructure and mechanical properties of a U-shaped profile were studied through optical microscopy,scanning electrical microscopy,transmission electrical microscopy,hardness,and tensile *** coarse equiaxed grains existed near the profile edge as a result of the dynamic recrystallization nucleation and exceeding growth during hot *** fibrous deformed and sub-structured grains located between the two coarse grain layers,due to the occurrence of work-hardening and dynamic *** needle β′′precipitates were distributed inside the grain,and obvious precipitates-free zone appeared after aging *** tensile strength,yield strength and elongation of the aged Al−Mg−Si alloy U-shaped profile were no less than 279.4 MPa,258.6 MPa,and 21.6%,*** fracture morphology showed dimple rupture *** precipitates and grain boundaries played key role in the strengthening contribution.

关键词： Al−Mg−Si alloy U-shaped profile hot extrusion microstructure mechanical properties precipitates

Creep age forming of 2124 aluminum alloy with single/double curvature

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Transactions of Nonferrous Metals Society of China 2013年第7期23卷 1922-1929页

作者：张劲邓运来李思宇陈泽宇张新明中南大学材料科学与工程学院长沙410083

In order to investigate the springback rules, the variation characteristics of physical property and microstructure in bending creep age forming process, a series of creep forming tests of 2124 aluminum alloy were conducted based on three kinds of single and double curvature forming tools. The results show that the spingback rate would be the minimum under the optimal coupling conditions among the temperature, aging time and internal stress state of material. Difference exists in the two directions of the formed sample with double curvature, but the curvature variation keeps the same. Yield strength, ultimate tensile strength and fracture toughness of the double curvature formed sample appear to be higher than those of the single curvature formed sample under the same aging condition, but the elongation and the anisotropy are opposite.

关键词： springback creep age forming double curvature bending 2124 aluminum alloy