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Effect of rolling strain on microstructure and tensile properties of dual-phase Mg-8li-3Al-2Zn-0.5Y alloy

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Journal of Materials Science & Technology 2018年第12期34卷 2256-2262页

作者： Wencai liu Shi Feng zhongquan li Jiong Zhao Guohua Wu Xianfei Wang Lv Xiao Wenjiang Ding National Engineering Research Center of light Alloy Net Forming and Key State Laboratory of Metal Matrix Composite School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Spaceflight Precision Machinery Institute Shanghai 201600China

This study was conducted to discuss the effect of rolling strain on microstructure and tensile properties of dual-phase Mg-8li-3Al-2Zn-0.5 Y（wt%） alloy, which was prepared by casting, and then homogenized and rolled at 200℃. The rolling process was conducted with 10% reduction per pass and five different accumulated strains, varying from 10% to 70%. The results indicate that the as-cast and as-rolled Mg-8li-3Al-2Zn-0.5Y alloys are composed of α-Mg, β-li, Alli and Al;Y phases. After rolling process,anisotropic microstructure was observed. a-Mg phase got elongated in both rolling direction and transverse direction with the addition of rolling strain. Consequently, the strength of the alloy in both directions was notably improved whereas the elongation declined, mainly caused by strain hardening and dispersion strengthening. The tensile properties of the as-rolled alloys in the RD, no matter the YS, UTS or the elongation, are higher than those of the TD due to their larger deformation strain and significant anisotropy in the hcp α-Mg phase. In addition, the fracture and strengthening mechanism of the tested alloys were also investigated systematically.

关键词： Mg–8li–3Al–2Zn–0.5Y Rolling Anisotropy Tensile properties Strain hardening

Effects of Ce-rich RE on microstructure and mechanical properties of as-cast Mg-8li-3Al-2Zn-0.5Nd alloy with duplex structure

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Progress in Natural Science:Materials International 2019年第1期29卷 103-109页

作者： Xiang Peng Guohua Wu Lv Xiao Hao Ji Jie Zhang Wenbing Zou zhongquan li Wencai liu National Engineering Research Center of light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong University Shanghai Spaceflight Precision Machinery Institute

The effects of Ce-rich RE on the microstructure and mechanical properties of as-cast Mg-8li-3Al-2Zn-0.5Nd-x RE(x = 0, 1, 2, 3 wt%) alloys were investigated. The results indicated that the as-cast Mg-8li-3Al-2Zn-0.5Nd alloy mainly consisted of α-Mg, β-li, Alli, Mgli2 Al and Al2 Nd phases. With the addition of Ce-rich RE in the alloy,Al3 RE and Al2 RE phases generated and gradually grew into net-like or block-like structure. With the addition of RE, Al-RE phases generated by consuming Al element and, thus, less Al element was dissolved in the matrix and less Alli phase formed. Furthermore, less Alli phase means that more li element released to cause the increase ofβ-li phase and refine the α-Mg phase. Under the influence of these factors, adding more RE led to higher elongation and lower tensile strength and hardness. With the addition of Ce-rich RE, the yield strength and ultimate tensile strength of the as-cast Mg-8li-3Al-2Zn-0.5Nd alloy gradually decreased from 180 to 152 MPa and from 215 to 193 MPa, respectively, while the elongation was remarkably improved from 21.1% to 40.2%.

关键词： Mg-li alloy Rare earth Ce Microstructure Mechanical property

Successor Characteristics of the Mesozoic and Cenozoic Songliao Basins

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Acta Geologica Sinica(English Edition) 2008年第3期82卷 622-628页

作者： li zhongquan Timothy KUSKY YING Danlinl GUO Xiaoyu li Hongkui State Key Laboratory of Oil and Gas Reservoir Geology and Exploration Chengdu University of Technology Chengdu Sichuan 610059 China Saint Louis University St. Louis MO 63103 USA Southwest Oil-Gas Field Company Chengdu Sichuan 610051 China

The Songliao basin is a complex successor basin that was initiated in the Mesozoic and experienced multiple periods of reactivation. Based on seismic and drilling data, as well as regional geologic research, we suggest that the Songliao basin contains several different successor basins resting on top of Carboniferous-Permian folded strata forming the basement to the Songliao basin. These basins include the Triassic-Mid Jurassic Paleo-foreland basin, the Late Jurassic-Early Cretaceous downfaulted basin, and an early Cretaceous depressed basin （since the Denglouku Group）. This paper presents a systematic study of the basin-mountain interactions, and reveals that there are different types of prototype basin at different geologic times. These prototype basins sequentially superimposed and formed the large Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin fills a Triassic-early Middle Jurassic gap in the geologic history of the Songliao basin. The paleo- foreland basin, downfaulted basin, and depressed thermal subsidence basin all together represent the whole Mesozoic-Cenozoic geologic history and deformation of the Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin plays an important role both for deep natural gas exploration and the study of basin-mountain coupling in north China and eastern China in general. This example gives dramatic evidence that we should give much more attention to the polyphase tectonic evolution of related basins for the next phase of exploration and study.

关键词： Mesozoic-Cenozoic Songliao basin Paleo-foreland basin successor basin

Experimental Insights on the Structural Patterns and Their Formation Mechanisms of the Xujiaweizi Fault Depression in the Songliao Basin

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Journal of Earth Science 2018年第2期29卷 369-375页

作者： Wei Long zhongquan li Ying li Junliang Chen Fengyu Tan Zhiyi Zheng Jinmiao Hu Runfang li State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of Technology Chengdu 610059 China Key Laboratory of Tectonic Controls on Mineralization and Hydrocarbon Accumulation of Ministry of Land and Resources Chengdu University Of Technology Chengdu 610059 China School of Geosciences King's Colleges University of Aberdeen Aberdeen AB24 3UE UK Exploration and Development Research Institute of Daqing Oilfild Company Ltd. Daqing 163712 China

The Xujiaweizi （XJWZ） fault depression is a primary area for deep-seated gas explo- ration in Daqing. Through seismic profile interpretation, the main sag-controlling fault and struc- tural characteristics in the XJWZ fault depression were analyzed based on folds and faults analysis. A three-dimensional geological model of the XJWZ fault depression was also set up to enable fur- ther discussion by means of structural physical modeling. According to our research, the basic structural framework of the XJWZ fault depression was the result of regional extension. Its forma- tion and evolution were mainly controlled by the Xuxi fault. The structural framework of S-N blocking was due to changes in the fracture attitude. The Xuzhong uplift and the depressions on both sides belong to a normal-fault-related fold and were formed by controlling of the ramp/flat normal fault in the same tectonic movement period.

关键词： structural physical modeling formation mechanism normal-fault-related fold Xujiaweizi fault depression.

Effect of B_4C on the Microstructure and Mechanical Properties of As-Cast TiB+TiC/TC4 Composites

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Acta Metallurgica Sinica(English Letters) 2014年第2期27卷 205-210页

作者： Jiheng Wang Xianglong Guo Lv Xiao liqiang Wang Weijie Lu Baohui li zhongquan li Di Zhang State Key Laboratory of Metal Matrix Composite Shanghai Jiaotong University School of Material Science and Engineering Jiangsu University of Science and Technology Shanghai Research Institute of Spaceflight Precision Machinery

Different additions of BaC were introduced into TC4 to alter the microstructure and mechanical properties. The morphologies of reinforcements are related to the solidification paths. The refinement of lamellar spacing 2 is based on the precipitation pattern of [3-phases. Microhardness, compression elastic modulus （Ec）, and elastic modulus of the matrix （Em） appear non-linear relationships with B4C additions. Due to the refinement of lamellar spacing with Hall-Petch-type relationships, and the solution strengthening of C on the α＋ β matrix, the effect of reinforcements on the mechanical properties will be more efficient when the additions of B4C are no more than 0.19 wt%. When the additions of B4C are more than 0.19 wt%, the efficiency will decrease.

关键词： Titanium matrix composites Lamellar spacing 2 Microstructure TiC TiB Nanoindentation

Surface preparation by mechanical polishing of the 1.3-GHzmono-cell copper cavity substrate prior chemical etching for niobium coating

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Radiation Detection Technology and Methods 2021年第1期5卷 33-41页

作者： Fuyu Yang Pei Zhang Jin Dai zhongquan li Institute of High Energy Physics(IHEP) Chinese Academy of Sciences(CAS)Beijing 100049China School of Nuclear Sciences and Technology University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Particle Acceleration Physics and Technology IHEPCASBeijing 100049China

Purpose Surface quality of the substrate is widely acknowledged to be essential for the niobium thin film deposition. Mucheffort has thus been spent to improve the surface roughness by using various chemical etching techniques. However, surfacepreparation before the chemical etching also plays a part in obtaining a satisfactory substrate, but has rarely been studiedbefore. This paper aims to define a specification for the pre-polished copper substrate prior chemical etching and searches forsuitable alternative non-chemical grinding methods for the copper *** Copper samples were mechanically pre-polished at first by using flap sanding wheels of different grits and thenchemically etched by using the well-established SUBU solutions. Surface roughness, as a figure of merit, was measuredand compared before and after SUBU. Optimum practice for pre-polishing may therefore be determined. The mechanicalgrinding was subsequently applied on the 1.3-GHz mono-cell copper cavity. Meantime, the previously reported centrifugalbarrel polishing method was also applied with new abrasive materials and modified schemes. A comprehensive study ofetching rate, surface roughness and morphologies was *** and conclusions The specification for surface roughness prior SUBU was determined. Due to a complex geometryand curved surfaces possessed by the 1.3-GHz copper cavity, the traditional mechanical grinding was proved to be not *** surface quality was obtained by using the alternative centrifugal barrel polishing on the cavity. The proposed newscheme and new abrasive materials were demonstrated to be effective, and a mirror-like surface was achieved on the coppercavity. The traditional mechanical grinding can therefore be replaced. This constitutes a dedicated study on pre-polishing ofthe 1.3-GHz copper cavity substrate prior chemical etching for niobium sputtering.

关键词： Copper substrate Surface roughness Mechanical grinding Centrifugal barrel polishing Abrasives SUBU

Status of water environment pollution in the Xixi Wetland and its ecological treatment countermeasures

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Frontiers in Biology 2009年第2期4卷 228-232页

作者： Wenyue CHEN Jiemin ZHENG zhongquan li Guozheng SHEN Yuchen li Institute of Crop Science Hangzhou Academy of Agricultural SciencesHangzhou 310024China Xixi Wetland Management Co. LtdHangzhou 310031China

In this paper,the water quality of the Xixi Wetland was evaluated and the characteristics of water pollution were described according to the survey *** on the status of water quality and its functional requirements as an urban wetland,biological-ecological countermeasures were *** experimental use of ecological technologies,such as artificial wetlands,ecological aquiculture and artificial floating island,were done in several fish ponds in the Xixi *** monitoring results show that the quality of the treated water has improved significantly and the measures to purify the eutrophic water in the wetland have been effective.

关键词： water environment pollution ecological treatment eutrophication Xixi Wetland

OFHC copper substrates for niobium sputtering:comparison of chemical etching recipes

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Radiation Detection Technology and Methods 2020年第2期4卷 139-146页

作者： Fuyu Yang Pei Zhang Jin Dai zhongquan li Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Purpose Niobium sputtered on copper has been a popular alternative approach for superconducting radio frequency(SRF)community in the last few *** to bulk materials of a few millimeters,high-purity niobium of merely a few microns is sufficient to realize superconductivity on the coated *** niobium thin film,it has been widely acknowledged that surface quality of the substrate plays a vital role in obtaining a superior niobium coating with excellent SRF ***,proper chemical treatment of the substrate before coating is crucial and the ultimate goal is to create a smooth and defect-free *** to the design of a cavity etching system,the mechanism of SUBU as well as two industry-used solutions is studied in detail on *** Copper samples were first pre-treated by mechanical grinding to remove fabrication damages,obvious defects and visible *** chemical solutions widely used in industries were subsequently chosen to etch the ***,the established SUBU solution was used independently on these pre-treated samples for *** morphology and etching rate were measured *** and conclusions Mirror-like copper surface was created by using the SUBU solution thus qualified for subsequent niobium sputtering,while the other two solutions used in industries were less effective with nonideal surface *** chemical reactions,the experimental requisites and the involved processes are extensively elucidated for all three *** for SUBU were examined,and the optimum ratio of the chemical bath volume to sample surface area was also *** investigations will serve as an important guidance for the development of a chemical etching system for elliptical copper cavities.

关键词： Chemical etching Copper substrate Dilute sulfuric acid SUBU Surface roughness

Microstructural Characteristics and Mechanical Properties of Cast Mg–3Nd–3Gd–xZn–0.5Zr Alloys

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Acta Metallurgica Sinica(English Letters) 2022年第6期35卷 922-940页

作者： He Xie Guohua Wu Xiaolong Zhang zhongquan li Wencai liu liang Zhang Xin Tong Baode Sun National Engineering Research Center of light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Spaceflight Precision Machinery Institute Shanghai 201600China

The microstructure,aging behavior and mechanical properties of cast Mg–3Nd–3Gd–x Zn–0.5Zr(x=0,0.5,0.8,1 wt%)alloys are investigated in this ***–Zr particles with different morphologies form during solution treatment due to the additions of *** the Zn content increases,the number density of Zn–Zr particles also *** comparisons of peak-aged studied alloys indicate that varying Zn additions could profoundly influence the competitive precipitation *** the peak-aged Zn-free alloy,β′′phases are the key strengthening *** 0.5 wt%Zn is added,besidesβ′′precipitates,additional fineβ_(1)precipitates *** the addition of 0.8 wt%Zn,the peak-aged 0.8Zn alloy is characterized by predominantly prismaticβ_(1)and scanty basal precipitate *** enhanced precipitation ofβ_(1)should be primarily attributable to the presence of increased Zn–Zr *** Zn content further increases to 1 wt%,the precipitation of basal precipitates is markedly *** precipitates andβ_(1)phases are the key strengthening precipitates in the peak-aged 1Zn *** tests reveal that the relatively best tensile properties are achieved in the peak-aged alloy with 0.5 wt%Zn addition,whose yield strength,ultimate tensile strength and elongation are 179 MPa,301 MPa and 5.3%,respectively.

关键词： Mg-Nd-Gd alloy Zn addition Competitive precipitation behavior Microstructural characterization