挤压比对双相Mg-8Li-6Zn-2Gd合金显微组织、织构和力学性能的影响

通过显微组织观察、织构分析和拉伸测试等手段研究挤压比对双相Mg-8Li-6Zn-2Gd合金显微组织、织构和力学性能的影响。结果表明:均匀化态Mg-8Li-6Zn-2Gd合金中含有α-Mg、β-Li、Mg Li Zn、I相和W相。经热挤压后,共晶I相被碾碎成细小颗粒状,而W相保持原有块状形状。合金中α-Mg基体和β-Li基体在热挤压过程中均发生了动态再结晶(DRX),且晶粒随着挤压比的增加逐渐细化。经热挤压后,α-Mg基体的基面织构弱化和柱面织构增强是由于非基面滑移的激活;β-Li基体中形成明显的α和γ纤维织构主要与动态回复与动态再结晶相关。热挤压同时提升Mg-8Li-6Zn-2Gd合金的抗拉强度和伸长率,并在挤压比为16:1时获得最佳的综合力学性能。

Lithium Ion Extraction from the High Ration Mg/Li Salt Lake Brine with Ionic Liquid in Triisobutyl Phosphate and Kerosene

1 Introduction As the lightest metal with the unique properties of energy production and storage,lithium is regarded as the new century energy metal.Lithium and its compounds were widely used in various industrial fields,especially in

Performance comparison of lithium fractionation from magnesium via continuous selective nanofiltration/electrodialysis

Although selective nanofiltration(SNF)and selective electrodialysis(SED)have been widely adopted in the field of Mg^(2+)/Li^(+)separation,their differences have not been illustrated systematically.In this study,for the first time,SNF and SED processes in continuous mode were studied for Li+fractionation from the same brine with high Mg/Li ratios and their differences were discussed in detail.For a fair analysis of the two processes,typical factors were optimized.Specifically,the optimal operating pressure and feed flow rate for SNF were 2.4 MPa and 140 L·h^(-1),respectively,while the optimal cell-pair voltage and replenishment flow rate for SED were 1.0 V and 14 L·h^(-1),respectively.Although the Li^(+)fractionation capacity of the two processes were similar,the selectivity coefficient of SNF was 24.7% higher than that of SED and,thus,the Mg/Li ratio in purified stream of the former was 19.0% lower than that of the latter.Due to higher ion driving force,SED had clear advantages in recovery ratio and concentration effects.Meanwhile,the specific energy consumption of SED was 20.1% lower than that of SNF.This study provided a better understanding and guidance for the application and improvement of the two technologies.

A 1000-year record of Mg/Li and Li/Ca ratios of ostracod shells in Lake Qinghai,NE Tibetan Plateau

1 Introduction Lake Qinghai,famous as the largest inland saline lake in China,located on the high-altitude northeastern Tibetan Plateau,and four junctional zones of the East Asian summer monsoon(EASM),Indian summer monsoon(ISM),East Asian winter monsoon and the westerly jet stream prevail,making it sensitive to global climate change

Microstructure and mechanical properties of AZ31 Mg alloy processed by high ratio extrusion

The microstructure and mechanical properties of AZ31 Mg alloy processed by high ratio extrusion (HRE) were investigated. General extrusion with extrusion ratio of 7 and high ratio extrusion with extrusion ratio 100 were contrastively conducted at 250,300 and 350℃. The results show that HRE process may be applied successfully to AZ31 Mg alloy at temperatures of 250, 300 and 350℃and this leads to obvious grain refinement during HRE process. The strength of HRE process is improved obviously compared with that of general extrusion. The grain refining mechanism of HRE process was also discussed. The current results imply that the simple high ratio extrusion method might be a feasible and effective processing means for refining the microstructure and improving the mechanical properties of AZ31 Mg alloy.

超轻高比强度Mg—Li系合金

密度为１．３ｇ／ｃｍ３左右而比强度高的Ｍｇ－Ｌｉ系合金对导航及与节能有关的汽车制造业等具有极大的吸引力。本文在对国内外研究结果进行综合分析的基础上，重点介绍了Ｍｇ－Ｌｉ系合金的性能及添加第三元素对Ｍｇ－Ｌｉ系合金组织结构、机械性能的影响。

尖晶石型Li_(0.9)Mg_(0.05)Mn_(1.95)O_4的合成及其性能

为了提高尖晶石型LiMn2O4材料的循环性能,采用掺杂金属的高温固相合成法合成了尖晶石型Li0.9Mg0.05Mn1.95O4材料,并以该材料作正极材料,中间相炭微球(MCMB)为负极材料,组装成562247型方型锂离子蓄电池。测试结果表明,750 ℃下烧结的尖晶石型Li0.9Mg0.05Mn1.95O4循环性能最好。在室温下,1 C充放电时电池比能量为83 Wh/kg和195 Wh/L,实际电池中所制材料比容量可达85 mAh/g,循环300次后电池的可逆容量变化很小。另外,还对电池的储存性能、倍率充放电性能及高低温性能进行了研究。

Li^+,Zn^(2+),Mg^(2+)掺杂Lu_2O_3∶Er^(3+)荧光粉的制备及发光特性

用微波高温固相法合成了Er^(3+)单掺Lu_2O_3,Li^+与Er^(3+)共掺Lu_2O_3及Li^+,Zn^(2+),Mg^(2+)掺杂Lu_2O_3∶Er^(3+)的荧光粉。实验表明金属离子Li^+、Zn^(2+)、Mg^(2+)、Er^(3+)掺杂Lu_2O_3,不影响Lu_2O_3的立方晶相。扫描电子显微镜测量表明,Li^+掺杂可以有效改善粉体的分散性和形貌,Li^+,Zn^(2+),Mg^(2+)共掺杂获得的粉体颗粒分布更加均匀,粒径范围为80～100 nm。379 nm激发下,Li^+与Er^(3+)共掺样品发光较单掺Er^(3+)样品在565 nm处的发光增强了4.5倍,而Li^+、Zn^(2+)、Mg^(2+)与Er^(3+)共掺样品较其发光增强5.3倍。980 nm激发下,Li^+与Er^(3+)共掺样品,Li^+、Zn^(2+)、Mg^(2+)与Er^(3+)共掺样品的发光分别比单掺Er^(3+)样品在565 nm处发光增强23倍与39倍,在662 nm处发光强度分别增强20倍与43倍。379 nm激发下,较单掺Er^(3+)的样品,掺杂Li^+的样品和Li^+,Zn^(2+),Mg^(2+)和Er^(3+)共掺的样品荧光寿命均有所增加,而Zn^(2+)、Er^(3+)共掺及Mg^(2+)、Er^(3+)共掺样品的荧光寿命则有所缩短。

Influence of Rare Earth Elements on Microstructure and Mechanical Properties of Mg-Li Alloys

A series of a-based Mg-Li-A1-Zn-xRE alloys were prepared. These alloys have low density ranging from 1.5 to 1.7 g·cm^-3 and high strength properties. The influence of RE element on the microstructure and the mechanical properties of these alloys were studied. The results indicate that the addition of RE （La, Pr, Ce） leads to the formation of rodshaped intermetallic compound Al2Zn2La distributed in the matrix. Al2Zn2La induces reduction of the laminar spacing and causes refinement of the microstructure. Therefore, this compound improves the strength of alloys at a high temperature.

Li(Ni_(0.8)Co_(0.15)Al_(0.05))O_(2)锂电池正极材料的水热-高温固相法合成及参数控制

文章采用水热-高温固相法制备了Li(Ni_(0.8)Co_(0.15)Al_(0.05))O_(2)阴极材料,采用SEM/XRD/TG-DSC对先驱体NCA-OH及NCA阴极材料的粉体性能进行了表征。结果表明,随反应温度的提高,NCA-OH/NCA颗粒尺寸逐渐增大,先驱体一次颗粒由细小的纳米片精细结构转变为纳米针状,NCA颗粒由花瓣状转变为纳米棒状。随反应温度和保温时间的延长,先驱体NCA-OH晶相结构没有发生明显的改变,较高温度可导致NCA的(003)晶面结晶度有所降低。另外,随反应时间的延长,I 003/I 104的峰强比逐渐增大,表明NCA正极材料层状结构中Li/Ni离子混排程度逐渐减轻。

吸附—膜耦合法从高镁锂比盐湖卤水中提锂

中国的锂资源主要赋存于高镁锂比盐湖卤水中,提锂难度较高,单一分离手段难以高效提锂,多种盐湖提锂技术的耦合是盐湖提锂的未来发展趋势。采用吸附—膜耦合法对盐湖卤水进行处理,在优化条件下实现了高选择性锂吸附,动态脱附后卤水镁锂比从105.2降低至1.49。考察了不同条件对纳滤膜分离纯化锂的影响。纳滤膜在稀释倍数1.0、温度20℃、操作压力0.4 MPa、pH 4.66、产水原料液比0.54的条件下,锂截留率为2.63%、分离因子为27.3、渗透通量为7.125 L/(m^(2)·h),最终产水镁锂比从最初的105.2降低至0.05,实现了对高镁锂比盐湖卤水中锂资源的绿色高效提取。

锂铝层状双金属氢氧化物的制备及其锂脱嵌过程

锂铝层状双金属氢氧化物(Li/Al-LDHs)是一种适用于高镁锂比卤水中提锂的吸附剂,但其存在吸附容量偏低、吸附机理与适用条件不够清晰等问题。本工作以铝粉、氢氧化锂为原料制备Li/Al-LDHs,考察了适用条件下溶液中阴阳离子对吸附过程的影响并进行了不同溶液组成下的提锂性能测试,结合红外光谱测试和X射线光电子能谱等表征明晰了锂脱嵌机理。结果表明,Li/Al-LDHs在卤水中的最大吸附容量为8.350mg/g,阳离子选择性顺序为Li^(+)>Na^(+)>Mg^(2+)>Ca^(2+)>K^(+)。Li/Al-LDHs对Li^(+)的吸附符合Langmuir等温吸附模型和准二级吸附动力学模型,吸附过程主要是基于尺寸筛分效应进行的,Li^(+)进入吸附剂层间的空位后需要等量的阴离子(Cl^(-)、SO_(4)^(2-)等)进行电荷平衡,其吸锂容量随溶液体系总离子浓度的增加而变大,因此更适用于从高含盐量卤水中提锂。研究结果可为后续废旧金属铝制取Li/Al-LDHs用于盐湖卤水提锂提供技术参考。

高Cu/Mg比AlCuMg合金的形变诱导Ω相析出强化

通过高分辨电子显微技术(TEM)、硬度测试、拉伸性能测试等手段研究了预变形对高Cu/Mg比AlCuMg合金180℃人工时效微观结构及力学性能的影响.结果表明,相对于传统时效T6处理,冷轧预变形(10%~60%)加后续人工时效的P-T6工艺使Al-CuMg合金的屈服强度提高了32%~69%,而延伸率保持在6%~13%.TEM表征发现T6工艺时效析出相为θ′相,而P-T6工艺时效析出相为Ω相和θ′相,Ω相的径厚比远大于θ′相,且数量上占总析出相的30%~75%.相对于θ′相而言,Ω相具有更好的强化能力和热稳定性.含Mg的AlCuMg合金可通过形变诱导Ω相析出,而不含Mg的AlCu合金不管是否变形均不析出Ω相.

基于LDH中间层的纳滤膜及其镁锂分离性能

实现盐湖卤水中镁锂的分离成为盐湖提锂过程中面临的巨大挑战,开发具有高镁锂分离性能的纳滤膜成为亟待解决的关键问题。通过化学刻蚀法获得了多孔层状双金属氢氧化物(layered double hydroxide,LDH)纳米片,然后将其沉积在聚丙烯腈多孔膜表面作为中间层,在该中间层上通过聚乙烯亚胺与均苯三甲酰氯界面聚合形成聚酰胺分离层,最终获得表面荷正电的LDH/聚酰胺纳滤膜。LDH中间层不仅增强了膜表面的荷正电性,且诱导聚酰胺层形成咖啡环结构,提高了膜表面的粗糙度,因此同步提高了膜的选择性和渗透性。当分离镁锂比为20的混合溶液时,LDH/聚酰胺纳滤膜的镁锂分离因子为17,渗透性为1.15×10^(-4)L/(m^(2)·h·Pa),且在实验时间(100 h)范围内性能稳定,展现出良好的镁锂分离应用前景。

离子液体/金属盐萃取体系用于高镁卤水提锂的研究

通过研究不同金属盐共萃剂、不同萃取体系对锂镁萃取率及离子液体阳离子损失率的影响,确定出最佳的萃取体系为1-辛基-3-甲基咪唑六氟磷酸盐([C_(8)mim]PF_(6))/六氟磷酸钠(NaPF_(6))/磷酸三丁酯(TBP)。考察了[C_(8)mim]PF_(6)浓度、NaPF_(6)浓度、相比对[C_(8)mim]PF_(6)/NaPF_(6)/TBP萃取体系锂镁萃取率及离子液体阳离子损失率的影响,确定最佳的[C_(8)mim]PF_(6)浓度为0.2 mol/L,NaPF_(6)浓度为0.2 mol/L,两者相比(体积比)为2.5;在最佳萃取条件下,锂的单级萃取率为80.5%,镁的单级萃取率为6.5%,离子液体阳离子损失率为2.6%。最佳反萃盐酸浓度为1.0 mol/L,反萃相比(体积比)为2.5;在最佳反萃条件下,锂和镁的反萃率分别为95.2%和99.0%。[C_(8)mim]PF_(6)/NaPF_(6)/TBP萃取体系能够实现锂的高效萃取,并且能够降低离子液体中阳离子的损失率,其可为用于高镁锂比卤水提锂的新型离子液体/金属盐萃取体系开发提供借鉴。

高压扭转大塑性变形对Al-Zn-Mg-Cu-Mn铝合金组织和织构的影响

对不同高径比的Al-Zn-Mg-Cu-Mn铝合金试样进行了高压扭转大塑性变形,并应用X射线衍射（XRD）与电子背散射衍射（EBSD）分析了合金大塑性变形时的微观组织变化。结果表明：合金在高压扭转大塑性变形后,Mg Zn2相进入到Al基中,初始组织在高压扭转剪切变形下发生拉长并细化。随着合金高径比的降低,其受到的扭转剪切效果不断上升。在高径比等于0.25时,小角度晶界的最大比例为0.522。合金（220）晶面具有最强的衍射峰,（111）晶面衍射峰比初始合金试样的衍射峰值更强。最大极密度值随高径比的降低而减小。

A Li_(3)P nanoparticle dispersion strengthened ultrathin Li metal electrode for high energy density rechargeable batteries

Achievement of lithium(Li)metal anode with thin thickness(e.g.,≤30µm)is highly desirable for rechargeable high energy density batteries.However,the fabrication and application of such thin Li metal foil electrode remain challenging due to the poor mechanical processibility and inferior electrochemical performance of metallic Li.Here,mechanico-chemical synthesis of robust ultrathin Li/Li_(3)P(LLP)composite foils(~15µm)is demonstrated by employing repeated mechanical rolling/stacking operations using red P and metallic Li as raw materials.The in-situ formed Li+-conductive Li_(3)P nanoparticles in metallic Li matrix and their tight bonding strengthen the mechanical durability and enable the successful fabrication of free-standing ultrathin Li metal composite foil.Besides,it also reduces the electrochemical Li nucleation barrier and homogenizes Li plating/stripping behavior.When matching to high-voltage LiCoO_(2),the full cell with a low negative/positive(N/P)capacity ratio of~1.5 offers a high energy density of~522 W·h·kg^(-1) at 0.5 C based on the mass of cathode and anode.Taking into account its facile manufacturing,potentially low cost,and good electrochemical performance,we believe that such an ultrathin composite Li metal foil design with nanoparticle-dispersion-strengthened mechanism may boost the development of high energy density Li metal batteries.

单核细胞计数与高密度脂蛋白比值联合单核细胞/大血小板比率检测对老年慢性阻塞性肺疾病急性加重期肺栓塞危险分层诊断效能

目的 探讨单核细胞计数与高密度脂蛋白比值(MHR)联合单核细胞/大血小板比率(MLPR)检测对老年慢性阻塞性肺疾病急性加重期(AECOPD)肺栓塞危险分层诊断效能。方法 回顾2018年5月至2022年5月长治市人民医院收治的233例老年AECOPD并发肺栓塞病人的临床资料,比较不同危险分层病人MHR、MLPR水平,并分析MHR、MLPR与危险分层的相关性。采用多元有序logistic回归分析明确MHR、MLPR与AECOPD肺栓塞危险分层的关系,并评估其对危险分层的预测价值。结果高危组病人MHR、MLPR分别为0.74(0.70,0.86)、1.83(1.52,2.10),高于非高危组的0.55(0.39,0.62)、0.80(0.59,1.27)(P<0.05);中高危组和中低危组的MHR分别为0.62(0.57,0.71)、0.39(0.31,0.56),MLPR分别为1.32(0.75,1.61)、0.64(0.55,0.90),高危组MHR、MLPR高于中高危组,中高危组高于中低危组(P<0.05)。Spearman分析显示,MHR、MLPR水平与危险分层均呈正相关(P<0.001)。多元有序logistic结果显示年龄>80岁、白蛋白降低、血肌酐升高、MHR升高、MLPR升高均是老年AECOPD伴肺栓塞中高危和高危分层的独立危险因素(P<0.05)。ROC分析显示,MHR、MLPR对肺栓塞高危与非高危分层诊断AUC及其95%CI为0.92(0.88,0.95)、0.93(0.89,0.96),低于二者联合诊断效能0.97(0.94,0.99)(P<0.05);MHR、MLPR单独对肺栓塞中危病人分层诊断AUC及其95%CI为0.89(0.83,0.93)、0.84(0.78,0.89),低于二者联合诊断效能0.95(0.91,0.98)(P<0.05)。结论MHR、MLPR可作为老年AECOPD肺栓塞病人早期危险分层的可靠参考指标。

废旧磷酸铁锂脱锂后的铁磷渣锂吸附性能

以磷酸铁锂正极粉脱锂后的铁磷渣为锂离子筛,高钠锂比的硫酸钠型卤水为原料,系统研究还原剂用量、锂浓度、锂钠比、吸附温度等对铁磷渣锂吸附性能的影响。结果表明,铁磷渣锂吸附性能随着还原剂用量、锂浓度、锂钠比和吸附温度的提高而提升;同时,锂钠选择系数与锂钠比呈正相关性,而与吸附温度呈负相关性。经过5次吸附-解吸附循环后,吸附和解吸附过程的溶损率分别低于0.15%和0.002%;同时,铁磷渣的吸附容量基本稳定在2.7mmol/g,Li/Na选择系数为3.88,表现出较佳的锂吸附性能和循环稳定性能。

高压扭转变形的Al-Zn-Mg-Cu-Zr合金显微组织及织构

在380℃变形条件下对不同高径比的Al-Zn-Mg-Cu-Zr合金试样进行高压扭转实验,借助于EBSD和XRD技术分析变形Al-Zn-Mg-Cu-Zr合金的显微组织、第二相粒子和织构的演变规律。结果表明:在高压扭转过程中,大量第二相粒子从过饱和Al基体中脱溶析出,显微组织明显细化,在部分三叉晶界处出现了细小的动态再结晶组织;材料织构强度随着高径比的减小而减弱;当高径比为0.20时,晶粒的择优取向方向也发生了明显变化,晶粒在<102>、<111>方向上出现了择优取向。