The Rare Earth Aluminium Alloys in China

The development and application of rare earth aluminium alloys began in the 1960s in China.The represen- tative work was the usage of rare earth metals in alumino-silicon alloys for piston.In the 1970s,its initial stage. rare earths were used in enhanced AIMgSi alloy transmission line and FeCr Al alloy electric heating wire.During its developing period(from 1980 to 1985),in the field of smelting,after the electrolytic preparation of RE-Al master alloys at relatively low temperature,a new technique was invented that rare earth compounds were added to commercial aluminium electrowinning cell to produce RE-Al alloys directly.It opened the way for the appli- cation of rare earths in industry on a large scale.In the field of application,it was found that the addition of rare earths could improve the conductivity and processing property of aluminium alloys.The application of rare earths to aluminium conductors and products had made a breakthrough progress.Since 1986,its golden age,the study,production and application of aluminium alloys containing rare earths have been developing at an amazing speed,running neck and neck with the application of RE in agriculture,textile dyeing,and cast iron.

Hydrogen Fixation Effect of Rare Earths in Pure Aluminium and Aluminium Alloys

The areal distribution of some elements in the rare earth bearing spheroidal phases in pure aluminium and Al-Mn alloys was studied by SIMS(secondary ion mass spectrometry).The results show that cerium,iron. silicon and hydrogen are significantly segregated in the phases.Thus the existence of hydrogen-rich rare earth bearing eompounds is confirmed.It indicates that the rare earths have a hydrogen fixation effect in aluminium and aluminium alloys.

Effect of CeO_2 on heat transfer and crystallization behavior of rare earth alloy steel mold fluxes

To improve the heat transfer capability and the crystallization property of the traditional mold flux, CaF_2 was replaced with B_2O_3. Then, the influences of CeO_2 on the heat transfer and the crystallization of the CaF_2-bearing mold flux and the new mold flux with 10 wt% B_2O_3 were studied using a slag film heat flux simulator and X-ray diffraction(XRD). The results revealed that the addition of CeO2 reduced the heat transfer by increasing the solid slag thickness and the crystallization of two mold fluxes. However, CeO_2 had less effect on the B_2O_3-containing mold flux compared with the CaF_2-bearing mold flux. According to the analyses, the CeO_2 contents in the CaF_2-bearing mold flux and the B_2O_3-containing mold flux should not exceed 8 wt% and 12 wt%, respectively. Therefore, these experimental results are beneficial to improve and develop the mold flux for casting rare earth alloy steels.

Effects of Copper-Zinc Alloy Doped with Rare Earth Elements on Crystal of Calcium Carbonate

A copper-zinc alloy doped with rare earth elements was prepared and the mechanism was demonstrated in a simulating boiler and circulating cooling water with rigidity 1 mmol·L-1. The polar curve and scale inhibiting ability of the alloy was tested by a corrosion measurement system and a scale inhibition evaluation system, respectively. Scale samples were characterized with SEM and XRD. It is found that the transfer of cations could be promoted by doping with proper rare earth elements, and the corrosion potentials descend by 25～126 mV. The results indicated that the copper-zinc alloy doped with rare earth elements has higher scale inhibiting ability of CaCO3. The growth of calcite was affected by zinc ions dissolved because of primary battery reaction, and the transition of calcium carbonate from aragonite to calcite was hampered resulting in the proportion of aragonite to calcite is changed from 1.7∶1 to 2.7∶1.

Investigation on Behavior of Rare Earth Element Cerium in Aluminum-Lithium Alloys by Internal Friction Method

The behavior of rare earth element Ce in 2090 Al Li alloys was studied by the method of low frequency internal friction.The results showed that rare earth element Ce can increase the activation energy of grain boundary and improve the grain boundary strength of alloys.Rare earth element Ce can decrease the tendency of softening of elastic modulus of 2090 Al Li alloys after heat cycle and keep high elastic modulus of initial state.

Development of Strip Casting Technology in Rare Earth Permanent Magnet Alloys and Hydrogen Storage Alloys in China

The SC technique is now being applied widely in material preparation, especially in rare earth functional materials in virtue of its advanced process and high performance product. The applications of SC technique in rare earth permanent magnet alloys and hydrogen storage alloys were analyzed integrative, on the basis of summary of SC technique development in this paper. The paper mainly includes development history of SC technology, effect of SC technology on alloy microstructure, application of SC technology in RE storage hydrogen alloy and sintered Nd-Fe-B alloy, development of SC equipment and SC product industry. At the same time, the paper points out the existing problem of SC products.

Effect of yttrium on thermal stability and crystallization behavior of Nd_(60)Fe_(20)Al_(10)Ni_(10) amorphous alloys

The effect of yttrium on the thermal stability and crystallization behavior of Nd-Fe-Al-Ni amorphous alloys was investigated using X-ray diffraction （XRD）, differential scanning calorimeter （DSC）, and transmission electron microscopy （TEM）.The results indicated that the as-cast Nd60Fe20Al10Ni10-xYx（X=-0, 2） amorphous alloys were fabricated with some quenched-in crystals, which could be restrained by Y. With the effect of yttrium, both the crystallization temperature and exothermic peak shifted to higher temperatures, illustrating that the thermal stability could be improved. The addition of Y changed the crystallization process and final crystallization results. Moreover, the crystallites in the amorphous matrix became more homogeneous and smaller. Meanwhile, Y was useful for the passivation of oxygen in chemistry and restrained the negative effect of oxygen. The activation energies of the start of crystallization and peaking were 1.21 and 1.16 eV, respectively, according to the Kissinger equation.

Study of the Coarse Blocky Compounds in the As－cast 7075 Aluminium Alloys Containing Rare Earth Elements

The coarse blocky compounds in the as-cast 7075 aluminium alloys containing rare earth elements, neodymium, cerium or mischmetal were investigated by means of transmission electron microscope with EDX and scanning electron microscope. The blocky compounds in these alloys were identified as rare earth compounds, (Cr, Ti)2 RE (Al, X)20 (X is magnesium, copper and zinc),body-centred cubic, with 184 atoms to the unit cell , lattice parameter 1.453￣1. 458 nm, Vickers hardness 4000￣5600 MPa and calculated density 3400 kg/m3. The results show that the amount of blocky compounds in the alloys decreases with decreasing of Ti and Cr content or with increasing of cooling rate during solidification.

Effects of Cerium on Texture and Mechanical Property of 2090 Aluminium-Lithium Alloys

In order to investigate the effects of Ce on mechanical anisotorpy of Al-Li alloys, the texture of 2090 AlLi alloy with different Ce content was determined using orientation distribution function technique, in which the mechanical properties with different angles to rolling direction were measured. The effects of Ce on texture and mechanical properties of 2090 alloys were discussed. The results show that the type of main texture of 2090 alloys is {225} <554>. Ce will not change the type of main texture of the alloy, but make the distributiodn of main texture scattered. Ce can change the volume fractions of ideal texture components and will decrease the anisotropy of yield strength, hence the content of the texture components that enhance the anisotropy of yield strength can be reduced.

Electrochemical impedance characteristics of LC4 aluminum alloy treated with ZH1 technique

Zhl technique was used to form a corrosion resistant layer on LC4alloy. the composition of the layer was studied by X-rayphotoelectron spectroscopy (XPS). It is found that the layer iscomposed of oxides of metals on the sub- strate, such as Al_2O_3,ZnO, MgO_, CuO, and MnO_2. The elecrochemical impedance spectrums(EIS) of LC4 aluminum alloy specimen were measured in NaCl solutionsto study the mechanism of the corrosion resistance of the alloytreated with Zh1 technique.

微量Ce添加对Al-Si-Fe铝合金微观组织及导热性能的影响

随着汽车零部件、通讯和电子产品的发展,其对铝合金的导热性能提出更高的需求,因此急需开发新型高强韧高导热铝合金材料。通过金相显微镜、扫描电镜、涡流电导率仪和万能力学性能测试仪等研究了微量Ce添加对Al-Si-Fe铝合金的微观组织、导电导热性能以及力学性能的影响。结果表明,稀土Ce添加量少于0.05%时对组织没有明显细化,0.07%Ce可以细化铝合金的微观组织,减少二次枝晶臂间距,初生α-Al相由粗大的枝状晶转化成胞状晶。当Ce含量为0.07%时,合金中出现亮白色的块状Al11Ce3相和灰白色针片状β-Al5FeSi相。稀土Ce元素的添加能提高合金的导电和导热性能,当添加0.07%Ce时,合金的导电率和导热率达到最佳值,导电率为36.6%IACS,导热率为153.97 W/(m·K)。随着微量稀土Ce元素的添加,合金的抗拉强度与屈服强度整体变化不大,抗拉强度为144.5 MPa,屈服强度为89.7 MPa,但伸长率有所提升。当添加0.07%Ce时,合金伸长率为4.54%,比未添加Ce时提升26.1%,这是由于微量Ce没有对组织产生足够的细化效果来提高强度,而使共晶Si和富铁相变质与细化,故提高了合金的伸长率。

The effect of LPSO on the deformation mechanism of Mg-Gd-Y-Zn-Zr magnesium alloy

The tensile deformation behavior and corresponding microstructure evolution of the Mg-4.7Gd-3.4Y-1.2Zn-0.5Zr(at.%)magnesium alloy with long period stacking structure(LPSO)are studied by electron backscatter diffraction(EBSD)and slip lines methods.The results show that less and very small size of twins is observed in the grains with high value of Schmid factor for twinning,which indicates that the growth of the{10–12}twinning deformation is prevented by the LPSO phase.The prismatic lines present in grains of which the prismatic slip Schmid factor is above 0.4.The favorable orientation and LPSO phase synergistically promote the activation of prismatic slip.The inhomogeneous rotation of the grains during deformation is the reason for the microcrack at grain boundary.

Magnetocaloric effect of(Tb_(1-x)Ce_x)Co_2 alloys in low magnetic field

The phases in alloys(Tb1–xCex)Co2 with x=0,0.1,0.2,0.3,0.4 and 0.5 were investigated by X-ray diffraction analysis,and the magnetocaloric effect for x=0–0.4 was studied by magnetization measurement.The samples were almost single phase with MgCu2-type cubic structure.The magnetization decreased with the increase of Ce.The Curie temperatures(Tc) of Tb1–xCexCo2 alloys with x from 0.1 to 0.4 were 180,165,160 and 152 K,respectively.For x=0.5 in the range from 100 K to 230 K,the point of magnetic transition was n...

Study on Characteristics of Crystal Growth of NdFeB Cast Alloys

The characteristic of crystal growth of NdFeB cast alloys was studied. It is found that the crystal growth orientation of conventional ingots is along <410> or <411>. As the cooling rate increases, the crystallization orientation changes from a axis to c axis, along which the grain is easy to be magnetized. Meanwhile, by analyzing the change of crystallization orientation, the influence on the property of magnets was discussed.

Structure of Sn Doped AB_5 Non-Stoichiometric Hydrogen-Absorbing Alloys-Ⅰ

Five non stoichiometric alloys, i.e., LaNi 5.15 , La(NiSn) 5.14 , La(NiSnCo) 5.12 , La(NiSnMn) 5.12 , and La(NiSnCoMnAl) 5.10 were studied. It is shown that the second minor phase does not exist in the major phase through the X ray diffraction analysis. By the measurements of the crystal lattice constant, the volume of crystal lattice decreases with the increasing of the amount of atom B in AB 5. It is more obvious when the element nickel in B is partially subsituted by other elements. For non stoichiometric alloys, the lattice volume greatly increases when Ni is partially substituted by Sn. The lattice constant is also effected by the addition of Mn, Co, and Al. By means of electrochemical measurements, the plateau pressure of hydrogen absorption/desorption is measured with the results that Sn, Co, Mn and Al decrease the plateau pressure.

Crystal Structure of Ni_(50)Mn_(29)Ga_(21)Tb_(1.2) Magnetic Shape Memory Alloy at Room Temperature

Martensitic transformations, martensitic structures and substructures of Ni50Mn29Ga21Tb1.2 shape memory alloy were studied by DTA, X-ray diffraction and electron diffraction. The results show that the mainly phase at room temperature has body-centred tetragonal structure with the lattice parameters ： a = b = 0.60 ran, c = 0.5546 nm; and has body-centred monoclinic with lattice parameters： a =0.616 nm, b =0.581 nm, c = 0.553 nm, β = 90.8° in some tiny area. The substructures of Ni50Mn29Ga21Tb1.2 at room temperature are twin.

Sm、Er稀土元素对铝合金性能的影响

铝合金在当前的社会发展中有着广泛的应用,是工业生产的主要产品之一。在铝合金生产中加入适量稀土元素,能够有效改善铝合金的组织结构,对于降低和去除铝合金中的有害杂质,提升铝合金的强度和韧性具有重要的作用。基于当前工业市场发展中对于铝合金的需求,文章以7075铝合金为主要研究对象,在7075铝合金中添加Sm和Er稀土元素,针对稀土元素对铝合金的性能影响进行分析,提出一种基于稀土元素的高强高导铝合金材料技术,并对该技术的具体应用过程进行论述。

稀土在铝合金中的作用及研究进展

根据铝合金的传统分类方法,系统总结了稀土在铸造铝合金和变形铝合金中的作用,特别是在变形铝合金各个合金系中的作用.作者发现,以往国内对稀土铝合金的研究主要集中在La、Ce、Y及混合稀土在铝及其合金中的作用和机理方面,对其他稀土元素在铝合金中的作用(诸如提高强韧性、耐蚀性及可焊性)研究甚少.作者在稀土元素的选择上进行了深入研究,结果发现稀土Er在铝及其合金中具有显著作用,Er元素不仅能细化铝合金晶粒还能显著提高合金的强韧性、耐蚀性,因此有必要对其进行进一步研究.

稀土在铝及铝合金中的作用

依据文献综合介绍了稀土对铝及铝合金的力学性能、热学性能、光学性能、电学性能、耐腐蚀性能和工艺性能的影响,探讨了稀土在铝及铝合金中净化、变质和合金化作用的微观机理,讨论了稀土铝合金发展中存在的问题。

铝合金新型净化熔剂的研究

介绍了 1种铝合金新型净化熔剂———稀土熔剂 ,讨论了新型熔剂的配方设计思路 ,初步验证了新型熔型的使用效果 。