Ti对Zr-Al-Ni非晶合金玻璃形成能力和热稳定性的影响

四元非晶形成体系中，具有相对较大玻璃形成能力和热稳定性的合金成分点位于该四元成分图的等电子浓度面和等原子尺寸面的交线上。本文以Zr60Al20Ni20非晶合金的电子浓度和原子尺寸为基础，根据等电子浓度和等原子尺寸判据，添加Ti元素，设计了一系列Zr-Ti-Al-Ni四元合金，分析了Ti元素对Zr-Al-Ni非晶合金玻璃形成能力和热稳定性的影响。研究发现，在较低的Ti含量情况下，样品主要由非晶相组成，Ti的加入降低了合金的热稳定性和玻璃形成能力。     

稀土Gd对FeCrMoCB合金非晶形成能力及力学性能的影响

通过添加不同含量的稀土Gd,采用铜模真空吸铸法制备出一系列直径不同的FeCrMoCBGd合金样品,借助X射线衍射仪(XRD)、示差扫描量热仪(DSC)、显微硬度仪及万能试验机,研究了添加稀土元素Gd对FeCrMoCB合金非晶形成能力及力学性能的影响.结果表明,当Gd添加量为2%(原子分数)时,FeCrMoCBGd系合金的非晶形成能力最好,非晶合金的最大直径可超过12mm;非晶合金系的晶化过程为二级晶化行为,其显微硬度随直径的增加呈下降趋势,随Gd含量的增加而增加;非晶合金系均表现为脆性,断裂方式为典型的脆性断裂.     

大块非晶形成合金液体的热物理性能与玻璃形成能力

大块非晶合金由于其优异的性能而成的具有很大潜力的新材料，而合金的玻璃形成能力（GFA）的大小是能否获得大块非晶合金的根本所在。因此研究合金的玻璃形成能力成为材料科学领域重要的研究课题。本文从液体热物理性能出发，结合在这些方面所做的研究工作对大块非晶形成合金液体的玻璃形成能力做了一些探讨，希望对大块非晶合的研究有所裨益。     

P对Fe基非晶合金玻璃形成能力及磁性能的影响

采用XRD、DSC、SEM、TEM和、VSM等检测方法研究了Fe(73.65-x)Ni1Al5Ga2PxB9.6Si3C5.75(x=6.65、7.65、8.65、9.65)系列合金的微观结构、玻璃形成能力及磁性能.实验结果表明,当x=8.65时,样品为非晶结构,并深入分析了此时结构中的原子团簇结构;当x=7.65时,合金为在非晶基体上析出的纳米晶结构;当x=6.65时,在非晶基体上出现了大量的晶态相复合组织.热力学分析显示,用参数7能更合理地表征合金的玻璃形成能力,为C1>C2>A4.当P含量为7.65%(原子分数)时合金具有较好的软磁性能,其矫顽力为6.0Oe,饱和磁化强度为149.4emu/g.     

大块非晶合金的形成能力

通过对Ｚｒ－,Ｌａ－,Ｆｅ－,Ｍｇ－,Ｔｉ－,Ｎｄ－基合金系中,Ｔｒｆ,ΔＴｘ,Ｓ,Ｕ,Ｋｇｌ五个参数与临界冷却速度Ｒｃ之间关系的讨论来预测这些新型大块非晶形成合金的形成能力;结果发现参数Ｔｒｇ,Ｊ不能有效地反映这些合金系的ＧＦＡ,而参数ΔＴｘ,Ｓ,Ｋｇｌ较好地代表了这些大块非晶形成合金的ＧＦＡ。．     

具有极大玻璃形成能力的多元大块非晶合金的研究进展

近十年来,一系列具有极大玻璃形成能力,极低的临界冷却速度的大块非晶合金相继被发现,各种新研制出的大块非晶合金有两个共同的特征：（１）具有多元合金成分;（２）具有较大的过冷液相区范围。本文综合评述了大块非晶合金的研究进展,最新成果,着重讨论了多元合金的玻璃形成能力及其改善途径。     

大块非晶合金的玻璃形成能力

对描述大块非晶合金玻璃形成能力(GFA)的各种判据△T*、Kg1、S、△Tx、Trg、FBMG,以及用理论公式、TTT曲线法、CCT曲线法计算的形成大块非晶所需的临界冷速Rc进行了分析和讨论.结果表明,这些大块非晶合金的GFA判据在一定程度上可以反映大块非晶合金的某些性质,但单一的判据不能直观地表征大块非晶合金的GFA大小,根据TTT曲线及CCT曲线得到的临界冷速Rc及所能制备的大块非晶合金的最大尺寸tmax是表征大块非晶玻璃形成能力的基本参量.     

大块非晶合金的形成能力

通过对Ｚｒ、Ｌａ、Ｆｅ、Ｍｇ、Ｔｉ、Ｎｄ基合金系中Ｔｒｇ、ΔＴｘ、Ｓ、Ｊ、Ｋｇｌ五个参数与临界冷却速率Ｒｃ之间关系的讨论来预测这些新型大块非晶形成合金的玻璃形成能力（ＧＦＡ）;结果发现参数Ｔｒｇ、Ｊ不能有效地反映这些合金系的ＧＦＡ,而参数ΔＴｘ、Ｓ、Ｋｇｌ较好地代表了这些大块非晶形成合金的ＧＦＡ。又由于Ｓ、Ｋｇｌ与ΔＴｘ成正比,所以将参数ΔＴｘ作为这些大块非晶形成合金ＧＦＡ最合适的判据;最后初步探讨了形成大ＧＦＡ的原因     

重稀土元素添加对Cu-Zr-Al合金非晶形成和力学性能的调控

稀土元素是改善非晶态合金形成能力和性能的重要添加剂,本文采用铜模吸铸法制备了一系列Cu50-x Zr46Al4REx(RE=Dy,Tb,Gd;x=0,1,2,3,4)非晶态合金,系统地探究了重稀土元素Dy、Tb、Gd添加对Cu-Zr-Al合金非晶形成能力(GFA)和力学性能的影响.实验结果表明加入重稀土元素Dy、Tb、...     

FeCoBSiNb (Y)合金的玻璃形成能力及磁性能研究

采用铜模真空吸铸法、X射线衍射仪(XRD)、示差扫描量热分析仪(DSC)及振动样品磁强计(VSM),研究稀土元素Y及Fe/Co比例变化对FeCoBSiNb(Y)系合金的玻璃形成能力、热稳定性及磁性能影响.实验结果表明,添加4%(原子分数)的Y有利于(Fe0.5 Co0.5)72B19.2 Si4.8Nb4合金玻璃形成能...     

稀土元素对AgCuNi合金铸态显微组织的影响

研究了稀土Y和复合稀土La、Y对AgCu-Ni合金铸态显微组织及力学性能的影响。研究结果表明,随着Y含量的增加,铸态组织晶粒尺寸减小,并由树枝晶逐渐转变为胞晶;稀土元素以化合物(AgCu)5RE形式偏聚在晶界上,当La、Y复合添加时,稀土元素呈共生态在晶界析出;随着RE含量的增加,AgCuNiRE合金显微硬度增加,当RE含量由0.6%增加到2.2%时,合金硬度值比AgCuNi合金增加了0.26~1.28倍。     

Magnetism of rare earth alloys

The main properties of the rare earth elements are discussed, emphasizing their magnetic properties. However, it is difficult to use these elements in practice, because their Curie points are located below room temperature. In order to take advantage of the properties of these substances, they can be alloyed with iron, cobalt, or nickel. The properties of the rare earth-cobalt alloys are discussed, the phase diagram and the crystal structures are described, and the ferrimagnetic behavior is explained. Alloys of interest for magnet applications are selected.     

Effect of dynamic strain aging on the appearance of the rare earth texture component in magnesium alloys

Binary Mg alloys were prepared containing Zn, Ce and Gd. These were extruded and the resulting mechanical properties were determined. The intensities of the rare earth (RE) texture components were measured and linked to the extrusion conditions. Tension and compression testing was carried out on samples taken from extruded bars and a Mg-0.5Ce cast alloy. Over particular temperature and strain rate ranges, dynamic strain aging (DSA) was observed. The ranges over which DSA occurred during testing are compared with the conditions under which the RE texture components were produced during extrusion. It is concluded that formation of the RE texture components can be enhanced by extruding when the rate sensitivity is negative, i.e. under conditions where DSA is taking place.     

Effect of rare earth Y addition on the microstructure and mechanical properties of high entropy AlCoCrCuNiTi alloys

A series of AlCoCrCuNiTiY_x (x values in molar ratio, x = 0, 0.5, 0.8, 1.0) alloys have been prepared using vacuum arc melting. Classical high entropy diffraction peaks corresponding to a BCC crystal structure and some Cu, Cr peaks are observed for the AlCoCrCuNiTi alloy. However, with the incorporation of rare earth element Y, the BCC diffraction peaks disappeared and were replaced by new compounds like Cu₂Y and AlNi₂Ti. A typical cast dendrite structure with Cu-rich dendritic regions and Cr-rich rosette-like shape precipitations are found in the AlCoCrCuNiTi alloy. In the AlCoCrCuNiTiY_x alloys, Y segregated preferentially to Cu and combined as bulky Cu₂Y compound. The maximum stress of the AlCoCrCuNiTi alloy is 1495 MPa, but reduces intensively after the incorporation of Y due to the formation of bulky Cu₂Y. For all the alloys, the compressive fracture mechanism is observed to be cleavage fracture.     

污泥样品中稀土元素的检测方法研究

取稀土工业园区的污水处理设施和受影响河流的的污泥样品,分别采用三种样品预处理方法(敞开式酸溶法、石墨加热消解和微波消解法)进行对比研究,结果表明:石墨消解法前处理污泥样品后,使用ICP-MS测定其中稀土元素(Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu),其方法简便快捷,检出限低,准确度好。     

Phase transformation occurring during the heat-treatment of magnesium rare earth alloys

This work discusses the phase transformations occurring and mechanical properties of a cast and extruded Mg-5%Y-4%Gd alloy, 90 and 20 mm in diameter bar, after various heat treatments. The influence of quenching temperature, artificial and natural ageing on microstructure, microhardness and mechanical properties is presented. It is demonstrated that the alloy strengthens during natural ageing and initially recovers during artificial ageing. An understanding of the alloy behavior leads to optimization of the heat-treatment procedures; the best combination of mechanical properties is obtained after artificial aging at 200° for 3 days.     

荧光传感器在稀土检测方面的研究进展

本文阐述了稀土元素的应用和检测现状,指出荧光传感器在稀土元素检测中具有灵敏度高、选择性好、设备简单等优点,介绍了三类荧光传感器的特点和构建原理,分析了荧光传感器在稀土检测方面的发展方向。     

Role of rare earth oxide coatings on oxidation resistance of chromia-forming alloys

Rare earths (RE) have been used to increase high temperature oxidation resistance of chromia and alumina forming alloys. The RE can be added as elements (or oxides) to the alloys or applied as oxide coatings to the alloy surface. This paper presents the effect of different RE oxide coatings and lanthanum chromite coatings on the high temperature oxidation behavior of Fe20Cr and Fe20Cr4Al alloys. The oxidation resistance of the Fe20Cr alloy increased with increase in ionic radius of the RE element in the coating. The RE oxides decreased chromia growth rate more than alumina growth rate. In extended cyclic oxidation tests that were carried out from peak temperatures of 900 °C, 1,000 °C and 1,100 °C to room temperature at cooling rates of 300 °C/s and 1,000 °C/s, the La₂O₃ coating increased cyclic oxidation resistance of the Fe20Cr alloy significantly more than the Pr₂O₃ coating. The role of RE in increasing overall oxidation resistance of chromia forming alloys is discussed.     

Mg2Si基热电材料的稀土掺杂优化

采用机械研磨-电场激活压力辅助合成(FAPAS)技术,快速合成了稀土Sc和Y掺杂的Mg2Si基热电材料,所得试样组织均匀、致密,试样的平均晶粒尺寸为1.5～2μcm,微量稀土元素不改变基体材料的组织形貌.分析表明两种稀土元素均在不同程度改善热电性能,其中掺杂0.427%(摩尔分数)Sc和0.173%(摩尔分数)Y的试样...