均匀化退火对Al-6Mg-0.4Mn-0.15Zr-0.04Sc合金时效行为和微观结构影响

采用显微硬度法,光学显微镜,扫描电镜和透射电镜探究了均匀化退火对Al-6Mg-0.4Mn-0.15Zr-0.04Sc合金Al3(Sc,Zr)相时效行为和Mg均匀性的影响。显微硬度结果显示,合金直接在Al-Mg合金的均匀化温度475℃单级退火时,峰值硬度为830 MPa,远低于等时退火时的峰值硬度920 MPa,表明单级均匀化退火时Al3(Sc,Zr)时效强化效果没有充分发挥。因此设计双级均匀化退火,第1级退火在275～350℃进行,使得Al3Sc相弥散析出,300℃具有最高的硬度峰值870MPa,之后进行475℃第2级退火,使得Zr包裹在Al3Sc相长大,硬度进一步上升至920MPa。微观结构分析显示双级退火相比于单级退火球形Al3(Sc,Zr)相更为细小弥散,因此具有更高的强化效果。合金经过300℃,7h+475℃, 15 h双级退火后,不仅枝晶处Mg的偏析完全消除,而且Al3(Sc,Zr)相可以细小弥散析出,从获得了更高强度和再结晶温度。     

Influence of intermediate annealing temperature on strength of repeat cold-rolled Al-Mg-Sc-Zr alloy

研究了中间退火温度对多道次冷轧Al-Mg-Sc-Zr合金力学性能的影响.结果表明: 在各道次轧制前采用 400 ℃/ 1 h中间退火, 合金强度无明显变化;采用450 ℃/1 h中间退火, 合金强度随加工次数增加而明显降低. 对其机理分析表明, 冷变形产生的高密度位错等缺陷在较高温度的中间退火过程中为Sc和Zr原子提供了快速扩散的通道, 促进了Al3(Sc, Zr)相颗粒的粗化. Al3(Sc, Zr)颗粒的粗化不但使其阻碍位错运动的能力降低, 而且还削弱了其对回复进程的抑制作用.两种因素的共同作用导致了退火态合金强度的下降.     

中间退火温度对多道次冷轧Al-Mg-Sc-Zr合金力学性能的影响

研究了中间退火温度对多道次冷轧Al-Mg-Sc-Zr合金力学性能的影响.结果表明:在各道次轧制前采用400℃/1h中间退火,合金强度无明显变化;采用450℃/1h中间退火,合金强度随加工次数增加而明显降低.对其机理分析表明,冷变形产生的高密度位错等缺陷在较高温度的中间退火过程中为Sc和Zr原子提供了快速扩散的通道,促进了Al3(Sc,Zr)相颗粒的粗化.Al3(Sc,Zr)颗粒的粗化不但使其阻碍位错运动的能力降低,而且还削弱了其对回复进程的抑制作用.两种因素的共同作用导致了退火态合金强度的下降.     

Al-9.0Zn-2.5Mg-2.5Cu-0.15Zr-0.2Sc合金中Al3(Sc,Zr)粒子的析出行为

采用金相显微镜、扫描电镜、透射电镜和能谱分析,研究了Al-9.0Zn-2.5Mg-2.5Cu-0.15Zr-0.2Sc合金中Al3(Sc,Zr)粒子的形貌及其细化合金铸态组织、提高合金性能的机理.从熔体中析出的一次Al3(Sc,Zr)粒子是α(Al)固溶体的有效形核剂,该粒子以亚稳的Ll2型Al3Zr为核心,形成富钪与富锆Al3(Sc,Zr)层相间排列的多层复合结构;铸态合金退火后,α(Al)基体内析出二次Al3(Sc,Zr)粒子,经450℃×3 2h退火,二次Al3(Sc,Zr)粒子尺寸为16 ～ 23 nm,与α(Al)基体完全共格,该粒子钉扎位错和亚晶界,阻碍合金再结晶过程,提高合金再结晶温度;合金经RRA处理后,抗拉强度、伸长率和电导率分别为:667.5 MPa、7.5％和37.8％ IACS,具有良好的综合性能.     

7×××铝合金退火过程中二次Al_3(Sc,Zr)粒子的析出行为

采用透射电子显微镜,研究含钪Al-Zn-Mg-Cu-Zr系铸态合金在退火过程中二次Al3(Sc,Zr)粒子的析出形貌、尺寸及分布。结果表明:含0.20%Sc的7系铝合金铸态试样在450℃退火2h后,α(Al)基体内析出呈豆瓣状的二次Al3(Sc,Zr)粒子;在450℃退火32h后,Al3(Sc,Zr)粒子尺寸为16～23nm;在450℃退火32h后的二次Al3(Sc,Zr)相与α(Al)基体完全共格。     

复合添加Sc、Zr、Ti对Al-Mg合金组织与性能的影响

采用布氏硬度计、金相显微镜、扫描电镜(SEM)和透射电镜(TEM)研究了微量Sc、Zr、Ti以及Mg含量对Al-Mg合金的显微组织与布氏硬度的影响。结果表明,单独添加Sc、Zr元素的合金与未添加的Al-Mg合金的铸态组织相比,合金的晶粒组织得到了一定的细化,复合添加Sc、Zr、Ti3种元素的合金铸态组织的晶粒细化程度更为明显。同时在Sc、Zr、Ti相同含量下,Mg元素的增加也能进一步细化合金的晶粒组织,这是由于Mg元素固溶强化的结果,使得合金的布氏硬度提高。对Al-10Mg-Sc-Zr-Ti合金进行均匀化退火处理后,合金的硬度较铸态组织提高了10%,这是Al3(Sc1-xZrx)、Al3(Sc1-xTix)及Al3(Sc1-x-yZrxTiy)大量沉淀相二次析出,弥散度增大、分布更加均匀的结果。     

挤压铸造对Al-Mg-Sc-Zr合金组织及力学性能的影响

为提高Sc在Al-Mg-Sc-Zr合金中的利用率,通过金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)以及拉伸试验等手段,研究了挤压铸造对Al-5.36Mg-0.40Mn-0.16Sc-0.14Zr合金沉淀相析出行为及相关力学性能的影响。结果表明,与金属型铸锭相比,挤压铸锭的晶界析出相分布更加弥散,初生微米级Al3(Sc,Zr)相的长大受到抑制,晶粒尺寸略有长大。不经过热处理,挤压铸锭的抗拉强度与伸长率都明显高于金属型铸锭,而屈服强度相当;经过350℃×12h时效处理后,挤压铸锭与金属型铸锭的基体中均析出纳米级的二次Al3(Sc,Zr)相,但挤压铸锭基体中析出的纳米级Al3(Sc,Zr)相更多,沉淀强化作用更加明显,其屈服强度比金属型铸锭高出约26MPa。     

Al-Mg-Sc-Zr合金中初生相的析出行为

利用扫描电子显微镜(SEM)和电子探针(EPMA)研究液态金属的冷却速率对Al-6Mg-0.2Sc-0.15Zr(质量分数,%)合金中初生相的结构、形貌及成分的影响。结果表明:在较低的冷却速率下(随炉冷却),液态金属中析出的初生相为L12结构的Al3(Sc,Zr)相和D023结构的Al3(Zr,Sc)相。初生Al3(Sc,Zr)相为Zr溶解在Al3Sc相中的固溶体,具有复杂的形貌和较高的体积分数;当冷却速率较大时(钢模具冷却),D023结构的Al3(Zr,Sc)相的析出受到抑制而形成L12结构的Al3(Sc,Zr)相或亚稳态的Al3(Zr,Sc)相;当冷却速率足够大时(铜模具冷却),α(Al)基体在较高的过冷度下快速结晶,初生相的形成完全受到抑制。     

钪对Al-Zn-Mg-Cu-Zr合金组织性能的影响

研究了微量钪对Al-Zn-Mg-Cu-Zr合金组织性能的影响,钪在铝合金中主要以2种形式的化合物存在,一种是合金凝固时从熔体中析出的一次Al3（Sc,Zr）相,另一种是合金铸锭均匀化时析出的二次Al3（Sc,Zr）相,前者是α（Al）晶粒细化剂,有效细化铸态晶粒,而二次Al3（Sc,Zr）粒子强烈钉扎晶粒内位错及亚晶界,有效阻止热轧、退火或固溶处理过程中合金再结晶.钪是产生强烈析出强化效应的合金元素,含0.30%Sc的Al-Zn-Mg-Cu-Zr合金的抗拉强度和延性显著高于不加钪的铝合金.     

同时添加钪、锆对Al-10Mg合金再结晶机制的影响

利用电子背散射衍射(EBSD)和透射电子显微镜(TEM)研究了Al-10Mg及Al-10Mg-0.1Sc-0.1Zr合金在热压缩过程中的组织演变及动态再结晶机制。结果表明：同时添加Sc、Zr能够明显细化Al-10Mg合金的铸态晶粒,热处理后,Sc、Zr能够形成与α-Al基体共格的Al₃(Sc,Zr) 相,这些沉淀相能够提高合金的热变形抗力;在变形过程中,Al₃(Sc,Zr)相能够钉扎位错运动、降低晶界及变形带处的位错密度,使位错在沉淀相周围聚集,因而改变了Al-10Mg合金内部位错增殖与湮灭的过程、进而使Al-10Mg合金动态再结晶方式由不连续动态再结晶(DDRX)转变为连续动态再结晶(CDRX)。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

正~~