晶化行为对TiZr基块体非晶合金腐蚀性能的影响

采用电化学方法研究了晶化行为对Ti35Zr30Be24Cu7.5Co3.5块体非晶合金在3mol/L HCl溶液中的腐蚀性能的影响。利用XRD、DSC和SEM对非晶合金的相组成、晶化行为及腐蚀形貌进行了分析。结果表明,Ti35Zr30Be24Cu7.5Co3.5非晶合金晶化后,由α-Ti+CuZr2+CoZr相组成;铸态非晶合金仍具有最佳的耐蚀性;经350℃退火1h后,合金部分晶化,自腐蚀电流密度与其非晶合金腐蚀电流密度在同一个数量级,耐腐蚀性能下降不大;晶化温度达到550℃时,合金完全晶化,耐蚀性变差。     

机械合金化Nd-11Fe-Ti合金和机械研磨NdFe11Ti化合物退火时的相转变

采用X射线衍射、初始交流磁性率和差热分析研究了机械合金化Nd-11Fe-Ti(原子比)合金粉和机械研磨NdFe11Ti化合物粉在退火过程中的相转变.球磨7 h后二者均由非晶相和Ti在α-Fe中过饱和固溶体组成.机械合金化粉末样品中的非晶相的晶化温度为620℃,晶化亚稳相为TbCu7结构的Nd(Fe,Ti)7,900℃以上退火时,亚稳相转变成ThMn12结构Nd(Fe,Ti)12相;机械研磨的NdFe11Ti化合物粉中非晶相在638℃晶化形成的Nd(Fe,Ti)7在1000℃以上退火向Nd(Fe,Ti)12相转变.这些差别归因于两种样品中Ti原子在非晶相与α-Fe相中分配的不同.     

枝晶增强Ti基复合材料的显微组织与力学性能

采用铜模吸铸法在TiNiCuSn合金系中添加难熔金属Nb,制备出了d3 mm Ti60Cu14Ni12Sn4Nb10棒状多相复合材料。对该合金的显微组织特征和相组成进行了分析,并对其室温压缩性能进行了测试。研究结果表明,Ti60Cu14Ni12Sn4Nb10的显微组织主要由β-Ti枝晶相、纳米晶化相和少量非晶相组成。该合金在室温下表现出较好的综合力学性能,其抗压断裂强度可达1.71 GPa,断裂应变约为17.7%,弹性模量为116 GPa。合金的断口分析结果表明,由于产生了塑性枝晶相,因此该合金具有较高塑性。     

放电等离子烧结合成晶化相增强的块状Ti66Nb18Cu6.4Ni6.1Al3.5细晶复合材料

基于改进的非晶形成合金体系,选取Ti66Nb18Cu6.4Ni6.1Al3.5合金为研究对象,通过放电等离子烧结机械合金化制备的非晶合金粉末,结合非晶晶化法,合成以高Nb含量的晶化β-Ti(Nb)延性相为基体的块状细晶复合材料.利用X射线衍射(XRD)、差示扫描量热仪(DSC)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和万能材料试验机等手段对合成的非晶合金粉末和细晶复合材料进行表征分析.结果表明球磨60h后,初始混合粉末绝大部分转变成了非晶相,其玻璃转变温度、晶化温度、晶化峰值温度和熔化温度分别为750K、830K、847K和1422K,表明Nb含量的增加显著提高合金体系的热稳定性.另外,合成的块状钛基细晶复合材料的显微结构为β-Ti延性相包围(Cu,Ni)-Ti2相,其相区尺寸均大于1μm.当升温速率为167K/min、烧结温度为1373K时,合成的复合材料密度、屈服强度、断裂强度和断裂应变分别为5.64g/cm3、1705.8MPa、2126.4MPa和5.4%.     

Fe基非晶及纳米晶合金的制备和电化学腐蚀行为

分别采用单辊甩带法和非晶晶化退火法制备出非晶及纳米晶合金Fe73.5Si13.5B9Nb3Cu1;利用DSC、XRD和TEM对该非晶合金的晶化行为进行了分析;并用电化学极化曲线的方法和电化学阻抗技术研究了该非晶合金经不同温度退火后在1mol/LHCl溶液里的电化学腐蚀行为。结果表明,该非晶合金的晶化过程出现2个阶段。当退火温度为500℃时,合金尚未晶化,仍保持非晶态;当温度达到550℃时,出现了晶化衍射峰,晶粒平均直径约13nm;当温度达到600℃时,晶粒平均直径约为15nm。经过退火得到的纳米晶合金的腐蚀电位大于未退火的非晶,且阳极电流密度变得更低,表明纳米晶状态时的耐腐蚀性能比非晶状态的更好。该非晶合金未退火、550℃退火和600℃退火时的EIS均由单一容抗弧构成,具有一时间常数;且随着退火温度升高,电化学反应电荷转移电阻在增大。     

Ni_(60)Nb_(40)与Ni_(40)Nb_(60)非晶合金的低温晶化行为

采用X射线衍射(XRD)、差热分析(DTA)和电子显微镜研究Ni60Nb40和Ni40Nb60快淬非晶的晶化行为。结果表明,在10 K/min加热速率下采用差热分析测得Ni60Nb40和Ni40Nb60的非晶初始晶化温度分别为913和917K,且两种非晶样品在低于各自初始晶化温度退火时均发生了晶化。其中,Ni60Nb40样品经763 K退火48 h后仍保持非晶态,而经873 K退火1 h后,则析出面心立方纳米晶颗粒;对于Ni40Nb60非晶合金,在763 K温度下退火48 h就发生晶化,析出面心立方纳米相。晶化样品中均发生明显的成分偏聚现象。结合金属玻璃中的微结构与动力学不均匀性以及β弛豫过程,初步探讨Ni60Nb40和Ni40Nb60快淬非晶相关低温纳米晶化行为的内在机制。     

Ti_(40)Zr_(40)Ni_(20)合金急冷薄带的组织与相变行为

采用单辊甩带法在不同转速下制备Ti40Zr40Ni20合金薄带,通过X射线衍射(XRD)和透射电子显微术(TEM)分析各样品的急冷组织,并结合热分析方法,研究它们加热时的组织演化行为与相变特征。研究结果表明:随着甩带速率从40 m/s下降到10 m/s,Ti40Zr40Ni20薄带样品中依次生成了单相非晶、非晶+β-Ti(Zr)混合相和单相准晶组织;除单相铸态准晶外,前两种急冷组织在温度接近300℃时开始失稳生成纳米尺度的准晶相,当温度上升到540℃附近,组织中出现了cF96-(Zr,Ti)2Ni大单胞面心立方相(点阵参数a≈1.2 nm)。     

Ni59Zr16Ti13Si3Sn2Nb7非晶合金的晶化动力学

利用差热(DSC)分析等方法研究Ni59Zr16Ti13Si3Sn2Nb7非晶合金的非等温晶化动力学.结果表明Ni59Zr16-Ti13Si3Sn2Nb7非晶合金的结构弛豫激活能(Eg)、晶化过程的形核激活能(Ex)和长大激活能(Ep)分别为568、616和640 kJ/molAvrami指数n值为3.51±0.03,n值不随加热温度的变化而变化,说明该非晶合金的晶化方式是多晶型晶化.原子尺寸差异和正负混合焓共存是Ni基非晶合金具有较高的热稳定性的主要原因.     

Zr55Al10Ni5Cu30块状非晶合金靠近玻璃转变点的等温纳米晶化

研究了Zr55Al10Ni5Cu30块状非晶合金靠近玻璃转变点等温晶化过程。结果表明：420℃退火5h,出现了尺寸为20nm左右的晶相,同时,非晶基体也出现了尺寸为1－2nm分布均匀的团簇状结构;退火10h,析出的晶相尺寸为20－50nm,所占的体积分数为40％;退火20h之后,非晶相完全转变为亚稳相,析出的晶相尺寸为50nm左右,并没有出现明显的长大现象。退火得到的晶相为Cu10Zr7,Zr2Ni及一些未能标定的相,这些相在420℃具有相对的稳定性,没有问题稳定相转变。退火后,残余非晶相的热稳定性降低。等温退火过程经历了从非晶相→团簇状结构→亚稳相的转变过程。     

Age Hardening of AlCrMoNiTi High Entropy Alloy Prepared by Powder Metallurgy

采用粉末冶金工艺制备了AlCrMoNiTi高熵合金,并对其铸态和退火态的微观组织和硬度进行了研究。结果表明,铸态合金由富(Cr,Mo)bcc固溶体枝晶相和富(Al,Ni,Ti)fcc固溶体枝晶间相组成。时效合金在900℃高温可获得最高硬度HV约为6150 MPa,在1000℃发生退火软化现象,但是其硬度HV仍保持在5160 MPa的高硬度水平。这表明,AlCrMoNiTi高熵合金具有优异的高温时效硬化特性。该合金在800℃时的时效硬化特性主要归因于细晶强化,在900℃时则归因于第二相(bcc2)的析出硬化。在1000℃时发生退火软化现象,其原因在于第二相的分解和晶粒粗化。     

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

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