Phases and microstructures of high Zn-containing Al–Zn–Mg–Cu alloys

Phases and microstructures of three high Zncontaining Al–Zn–Mg–Cu alloys were investigated by means of thermodynamic calculation method, optica microscopy（OM）, scanning electron microscopy（SEM）energy dispersive spectroscopy（EDS）, X-ray diffraction（XRD）, and differential scanning calorimetry（DSC） analysis. The results indicate that similar dendritic network morphologies are found in these three Al–Zn–Mg–Cu alloys. The as-cast 7056 aluminum alloy consists of aluminum solid solution, coarse Al/Mg（Cu, Zn, Al）2 eutectic phases, and fine intermetallic compounds g（MgZn2）. Both of as-cast 7095 and 7136 aluminum alloys involve a（Al）eutectic Al/Mg（Cu, Zn, Al）2, intermetallic g（MgZn2）, and h（Al2Cu）. During homogenization at 450 ℃, fine g（MgZn2） can dissolve into matrix absolutely. After homogenization at 450 ℃ for 24 h, Mg（Cu, Zn, Al）2 phase in 7136 alloy transforms into S（Al2Cu Mg） while no change is found in 7056 and 7095 alloys. The thermodynamic calculation can be used to predict the phases in high Zncontaining Al–Zn–Mg–Cu alloys.

Characterization of ^(68)Zn uptake,translocation,and accumulation into developing grains and young leaves of high Zn-density rice genotype

Zinc(Zn) is an essential micronutrient for humans,but Zn deficiency has become serious as equally as iron(Fe) and vitamin A deficiencies nowadays.Selection and breeding of high Zn-density crops is a suitable,cost-effective,and sustainable way to improve human health.However,the mechanism of high Zn density in rice grain is not fully understood,especially how Zn transports from soil to grains.Hydroponics experiments were carried out to compare Zn uptake and distribution in two different Zn-density rice genotypes using stable isotope technique.At seedling stage,IR68144 showed higher 68Zn uptake and transport rate to the shoot for the short-term,but no signifi-cant difference was observed in both genotypes for the long-term.Zn in xylem sap of IR68144 was consistently higher,and IR68144 exhibited higher Zn absorption ratio than IR64 at sufficient(2.0 μmol/L) or surplus(8.0 μmol/L) Zn supply level.IR64 and IR68144 showed similar patterns of 68Zn accumulation in new leaves at seedling stage and in de-veloping grains at ripening stage,whereas 68Zn in new leaves and grains of IR68144 was consistently higher.These results suggested that a rapid root-to-shoot translocation and enhanced xylem loading capacity may be the crucial processes for high Zn density in rice grains.

Microstructures and mechanical properties of high strength Mg-Zn-Mn alloy

The microstructures and mechanical properties of a new Mg-6%Zn-1%Mn(mass fraction) wrought magnesium alloy were studied,which could be extruded smoothly at 310-330℃with a complete dynamic recrystallization.After solution treatment one and two-step aging techniques were used.All as-aged microstructures contained two types of dispersed phases:β' phases and pureα-Mn particles.The two-step aging had a better strengthening effect than the traditional one-step aging,and the strength value achieved by the two-step aging could reach that of the ZK60 wrought magnesium alloy.The outstanding precipitation strengthening effect of the alloy should be attribute to the GP zones,diffusive solute-rich zones and some metastable phases formed during the first step aging that provide more effective nuclei for Mg-Zn strengthening phases during the second step aging.

Effects of high pressure on the microstructure and hardness of a Cu-Zn alloy

The microstructure of a Cu-Zn alloy treated under different high pressures was investigated by means of metallographic, scanning electron microscope （SEM）, energy dispersive spectrometer （EDS）, and X-ray diffraction （XRD）, and the hardness of the Cu-Zn alloy was also measured. The results show that the ct phase with a smaller grain size, different shapes, and random distribution appears in the Cu-Zn alloy during the solid-state phase transformation generation in the temperature range of 25-750℃ and the pressure range of 0-6 GPa. The amount of residual α phase in the microstructure decreases and then increases with increasing pressure. Under a high pressure of 3 GPa, the least volume fraction of residual a phase was obtained, and under a high pressure of 6 GPa, the changes of the microstructure of the Cu-Zn alloy were not obvious. In addition, high pressure can increase the hardness of the Cu-Zn alloy, but it cannot generate any new phase.

静电纺丝法制备SnSbCuFeZn高熵合金/碳纳米纤维复合负极材料

采用静电纺丝技术,结合煅烧工艺,将SnSbCuFeZn高熵合金纳米颗粒均匀地锚定在导电互联的碳纳米纤维中,成功制备了SnSbCuFeZn@CNFs锂离子电池复合负极材料。结果表明,煅烧温度对材料的物相组成和形貌特征有重要影响,且直接影响SnSbCuFeZn高熵合金纳米颗粒的晶相、尺寸和分布,决定SnSbCuFeZn@CNFs电极的电化学性能。其中SnSbCuFeZn@CNFs-900电极展现出优良综合性能:0.1 A/g时,初始放电比容量达1232.8 mA/g,循环200次后可逆放电比容量保持在786.0 mA/g;1.0 A/g时,循环500次后放电比容量仍有433.8 mA/g;2.0 mV/s扫描速度下,赝电容贡献率高达93.37%。

高Zn含量Al-Zn-Mg-Cu系合金的热处理技术研究综述

综述了高Zn含量(质量分数不小于7%)Al-Zn-Mg-Cu系合金的研究现状,重点介绍了高Zn含量Al-Zn-Mg-Cu系合金热处理技术(均匀化处理、固溶处理、时效处理及形变热处理)的研究近况,阐述了不同热处理技术对高Zn含量Al-Zn-Mg-Cu系合金组织性能的影响机制,展望了高Zn含量Al-Zn-Mg-Cu系合金发展趋势及前景,旨在为Al-Zn-Mg-Cu合金综合性能的提升及铝合金材料产业的持续发展提供参考。

Synchrotron X-Ray Diffraction Studies on the New Generation Ferromagnetic Semiconductor Li(Zn,Mn)As under High Pressure

The pressure effect on the crystalline structure of the I-II- V semiconductor Li（Zn,Mn）As ferromagnet is studied using in situ high-pressure x-ray diffraction and diamond anvil cell techniques. A phase transition starting at -11.6GPa is found. The space group of the high-pressure new phase is proposed as Pmca. Fitting with the Birch-Murnaghan equation of state, the bulk modulus B0 and its pressure derivative B0 of the ambient pressure structure with space group of F43m are B0 = 75.4 GPa and B0 = 4.3, respectively.

Sc和Zr的复合添加对高Zn含量7xxx系铝合金组织演变和力学性能的影响

本文采用传统铸造和热加工工艺制备复合添加Sc、Zr的高Zn含量7xxx系铝合金,通过室温拉伸实验、扫描电子显微镜、X射线衍射仪和透射电子显微镜等,研究Sc、Zr的复合添加对高Zn含量7xxx系铝合金显微组织和力学性能的影响。结果表明:设计制备的新型高Zn含量(w(Zn)=10.9%)铝合金的抗拉强度为769 MPa,伸长率为4.7%。合金中高含量的Zn有利于形成高密度的纳米η'相,实现优异的沉淀强化效果。Sc和Zr复合添加形成的初生Al3(Sc,Zr)相有助于细化凝固组织,而时效过程中析出的次生Al3(Sc,Zr)相则可以有效抑制再结晶和阻碍位错运动,二者结合实现了良好的晶界强化作用。

Effects of ultrasound on the desulfurization performance of hot coal gas over Zn-Mn-Cu supported on semi-coke sorbent prepared by high-pressure impregnation method

Zn-Mn-Cu/SC（U） sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke（SC）as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitrate as active component precursors.The desulfurization performances of hot coal gas on the prepared sorbent at a mid-temperature of 500°C were tested in fixed-bed reactor.Morphology and pore structure of the prepared sorbent were also characterized by TEM,N2adsorption/desorption isotherms and XRD.For comparison,the sorbent of Zn-Mn-Cu/SC prepared by conventional high-pressure impregnation was also evaluated and characterized in order to study the effects of ultrasound treatment.Zn-Mn-Cu/SC（U） sorbent prepared by high-pressure impregnation under ultrasound-assisted condition showed a better desulfurization performance than Zn-Mn-Cu/SC.It could remove H2 S from 1000×10-6m3/m3 to 0.1×10-6m3/m3 at 500°C and maintained for 12.5 h with the sulfur capacity of 7.74%,in which both the breakthrough time and sulfur capacity were about 32% and 51% higher than those of Zn-Mn-Cu/SC sorbent.The introduction of ultrasound during high-pressure impregnation process greatly improved the morphology and pore structure of the sorbent.The ultrasonic treatment made particle size of active components smaller and made them more evenly disperse on semi-coke support,which provided more opportunities to contact with H2S in coal-based gases.However,there were no any difference in compositions and existing forms of active components on the Zn-Mn-Cu/SC and Zn-Mn-Cu/SC（U） sorbents.

热喷涂高铝含量Zn-Al合金涂层热带岛礁大气环境腐蚀行为研究

目的 研究Zn-Al合金涂层在热带海洋大气环境中的腐蚀行为,为低合金钢长效防护涂层的选用提供依据。方法 采用电弧热喷涂和高铝合金丝制备高铝含量Zn-Al合金涂层,通过户外暴露试验,采用目视、扫描电镜及能谱仪、金相显微镜、XRD、电化学交流阻抗谱和动电位极化曲线等方法,对不同暴露周期的涂层宏观、微观表面形貌、成分组成、截面形貌、腐蚀产物组成、电化学性能和腐蚀速率等进行观察、测试。结果Zn-Al合金涂层是以质量比为50%:50%的Zn/Al合金组成。在0~540 d周期内,涂层腐蚀产物主要由碱式锌铝碳酸盐化合物Zn_(6)Al_(2)(OH)_(16)CO_(3)·H_(2)O和羟基锌铝碳酸盐化合物Zn_(0.70)Al_(0.30)(OH)_(2)(CO_(3))_(0.15)·x H_(2)O、Zn_(0.71)Al_(0.29)(OH)_(2)(CO_(3))_(0.145)·x H_(2)O等组成,其对涂层孔隙进行填充。相对于初始涂层,180、360、540 d腐蚀后,涂层的极化电阻增加1个数量级,自腐蚀电位增加了约200 m V,自腐蚀电流密度降低至30%左右。结论 该Zn-Al合金涂层在腐蚀后保持较低且稳定的腐蚀速率,具有较好的耐腐蚀性能,致密且黏性的腐蚀产物对涂层孔隙起到了自封闭作用,显著提高了涂层的耐蚀性。

Effects of Ni-Doping on Microstructures and Properties of Zn-20Sn High-Temperature Lead-Free Solders

In the present work, the effect of Ni doping on the microstructures and properties of Zn-20 Sn high temperature lead-free solder has been investigated. Interestingly,Ni was present as the form of Ni-Zn compounds in the microstructure of Zn-20 Sn-xNi alloy.When the Ni-doping amount was 0.2~0.4 wt.%, the presence of δ phase was found, and when the doping amoun was 0.8 wt.%, the presence of γ phase was observed. With the increase of Ni content, the liquidus temperature increased but the solidus temperature did not change obviously. In addition, the microhardness and electrical resistivities of Zn-20 Sn-xNi solder increased gradually. And the spreading area and shear strength increased firstly but decreased afterwards. When the content of Ni was 0.4 wt.%, the spreading area and shear strength of solder reached to be maximum. After the addition of 0.4 wt.% Ni, the microstructure of the interfacial intermetallic compound(IMC) layer of the interface didn't change, but the total thickness of the IMC layer reduced. The δ-phase was embedded in the grain boundary of ε-Cu Zn5, which hindered the diffusion of atoms. The thickness of IMC layer at the interface reduced, which led to the improvement of the shear strength of the interface.

Effect of high Pressure on the Solid-State Phase Transformation Microstructure of Cu-Zn Alloy

The solid-state phase transformation microstructure of Cu-Zn alloy under different high pressure were investigated by means of SEM and XRD. The results show that the α phase with smaller grain size, different shape and random distribution appears in the Cu-Zn alloy, when the solid-state phase transformation generation in the Cu-Zn alloy under 25～750 ℃ and 3～6 GPa high pressure, and the volume fraction of transformation phase decreases with increasing pressure, under high pressure (6 GPa), the changes of microstructure of Cu-Zn alloy is not obvious. In addition, the effect of high pressure on the solid-state phase transformation microstructure of Cu-Zn alloy was discussed.

采用高压固溶制备具有均匀腐蚀行为的高强度抗菌Zn-4Ag-Mn合金

采用高压固溶(HPS)法制备Zn-4Ag-Mn合金,获得高强度、可均匀降解、抗菌的植入材料。显微组织表征表明,HPS处理使Zn-4Ag-Mn合金晶粒比铸态(AC)合金的细化57.9%,其第二相平均尺寸减小到10.2μm。压缩、维氏硬度和磨损摩擦试验表明,HPS合金具有较高的力学性能,抗压屈服强度为333.5MPa,维氏硬度为Hv 89.5。电化学腐蚀和浸泡腐蚀试验表明,HPS处理优化合金的耐蚀性,使其腐蚀均匀。此外。经抗菌实验测试,HPS处理的Zn-4Ag-Mn合金具有优异的抗菌性能,抗菌率为71.6%。这些结果表明,HPS处理的Zn-4Ag-Mn是一种很有前途的生物可降解植入材料。

基于^(6)LiF/ZnS(Ag)和导光束的微型耐高温中子探测器设计与测试

堆内中字注量率的测量对于反应堆的安全运行至关重要。闪烁体光纤中子探测器因其工作稳定、抗干扰能力强以及能够深入狭窄空间的特性在堆内中字注量率在线监测中发挥重要作用。将^(6)LiF/ZnS(Ag)混合材料和导光束相结合,设计了一种微型耐高温中子探测器。使用蒙特卡罗软件Geant4和光学仿真软件Trace Pro完成了探头结构的优化设计,并采用毛细玻璃管解决了粉末状闪烁材料在形状应用上的限制,显著提高了光产率。利用中国核动力研究院零功率实验堆和南华大学中子实验放射源进行了性能测试,结果表明探测器高温工作稳定性好、计数率高、响应灵敏以及γ抑制能力强,具备相对中字注量率在线监测能力,为将来适用于更高温度环境的高计数率微型闪烁体中子探测器的研制奠定了坚实基础。

Effect of heat treatment on high-cycle fatigue behavior of Mg-Zn-Y-Zr alloy

High-cycle fatigue (HCF) behavior of as-forged-T5 Mg-Zn-Y-Zr wrought alloy with stress-ratio R=-1 at ambient environment was presented. The relationship between the maximum stress and the number of cycles to failure was constructed. The results show that the fatigue strength at 107 cycles of the as-forged alloy in T5 state is higher than that of the alloy in T4 state. However, in T6 state, the fatigue strength at 107 cycles is higher than those of the alloys in both T5 and T4 states.

国产Zn-5%Al-混合稀土合金镀层高钒封闭索丝耐久性研究

以国家速滑馆首次应用的国产Zn-5%Al-混合稀土合金镀层高钒封闭索丝为研究对象,对其使用性能、基本特性及耐久性等进行研究。采用了国家速滑馆内部高空索体实际服役环境处的大气暴露试验方式,综合考虑索在加工安装过程中易产生的损伤,对索丝试件进行了划痕、刮擦、焊点的预制缺陷设计,研究了含预制缺陷的国产Zn-5%Al-稀土合金镀层高钒封闭索丝在真实使用环境中的大气腐蚀行为规律,并采用力学性能测试研究了索丝在服役环境大气腐蚀作用下的力学性能变化规律及不同缺陷对力学性能的影响。结果表明,加工安装过程中在索丝表面合金镀层产生的划痕、刮擦、焊点等损伤,会破坏合金镀层的完整性。大气暴露试验和力学性能试验中,三类缺陷对索丝金属镀层防大气腐蚀性能和单丝抗拉强度均有负面影响,其中焊点缺陷影响最大,单丝抗拉强度下降约40%。

Mg-Gd-Y-Zn-Zr系高强稀土镁合金研究现状及发展趋势

由于镁合金室温下塑性差,高温下强度较低,限制了它在诸多领域的应用发展。近年来国内外学者陆续开发出了含长周期堆垛有序结构相的Mg-Gd-Y-Zn-Zr系高强稀土镁合金,并对该合金系制备加工时组织性能的变化及机理进行深入研究。文章综述了近年来Mg-Gd-Y-Zn-Zr系高强稀土镁合金的研究现状及进展,分析了合金成分、常规塑性加工技术及热处理等对合金组织性能的影响,并展望该合金的研究方向。

高温煅烧Zn-MOF制备ZnO^(*)并用于光催化降解四环素

以对苯二甲酸和4,4'-双(咪唑基)-二苯基醚为配体,采用溶剂热法合成了锌基金属有机框架材料(Zn-MOF),再经高温煅烧制备了ZnO^(*)(*代表氧空位)。使用X射线粉末衍射(XRD)对产物的物相进行了表征,使用紫外-可见漫反射光谱仪对Zn-MOF和ZnO^(*)的带隙宽度进行了分析。分别以紫外光和可见光为光源,四环素(TC)为目标污染物,通过光催化降解实验,对Zn-MOF和ZnO^(*)光催化降解四环素的性能进行了探究。实验结果表明,在太阳光驱动下,相较Zn-MOF,ZnO^(*)对四环素的催化降解性能得到了大幅提升。

熔体冲击法增材制造技术对高合金化Al-Zn-Mg-Cu合金组织的影响

利用直读光谱分析仪、金相显微镜、扫描电镜、能谱仪等检测设备,探究熔体冲击法增材制造高合金化Al-Zn-Mg-Cu合金铸锭的组织特性。研究结果表明:相比于浇铸铸锭,熔体冲击法获得的打印铸锭在高度方向上具有更均匀的成分;晶粒尺寸细小,晶粒形貌由树枝晶转变为等轴晶或等轴枝晶;主合金元素Zn、Mg、Cu的晶内固溶量明显提高,晶界上的第二相明显减少;在同样的均匀化退火温度下,打印铸锭可以在更短的时间达到理想的效果,从而可降低成本,提高生产效率。

Al-Zn体系高压扭转过程中的相变机理

本工作对常温不互溶的Al-Zn体系进行了高压扭转下的机械合金化研究。将0.03 mm厚的纯Al和纯Zn交替堆叠,在3 GPa的压力下进行50圈的高压扭转处理。结果表明,高压扭转处理的Al-Zn合金中产生两种类型的相变,即晶体到非晶的相变,以及密排六方到面心立方的相变。局部高密度位错可能是Al-Zn合金从晶态转变到非晶态的主要原因,而HCP→FCC相变则归因为密排面原子沿晶界产生的Shockley不全位错的滑动。此外,本工作为深入研究Al-Zn合金的固态相变提供了一种新的途径,为提高铝锌合金的力学性能提供了新的思路。