Magnetic Properties and Phase Transformation of Tb1-xPrxFe1.96 （x=0 to 0.7） Compounds

In recent years,the fields of application of the(Tb,Dy)Fe2giant magnetostrictive materials,as ad-vancedfunctional materials,have become wider.Suchmaterials can be composed by pseudo-binaryRExRE′1-xFe2compounds that have the same sign ofmagnetostriction but the opposite sign of anisotropy,inorder to mini mize the magnetic anisotropy while stillmaintaining a large positive magnetostriction[1].Ac-cordingto Steven′s calculation,inthe magnetocrystal-line anisotropy and mangetostriction of rare…     

Review of Microstructure Evolution in Hypereutectic Al–Si Alloys and its Effect on Wear Properties

Al–Si alloys with silicon content more than 13 % are termed as hypereutectic alloys. In recent years, these alloys have drawn the attention of researchers due to their ability to replace cast iron parts in the transportation industry. The properties of the hypereutectic alloy are greatly dependent on the morphology, size and distribution of primary silicon crystals in the alloy. Mechanical properties of the hypereutectic Al–Si alloy can be improved by the simultaneous refinement and modification of the primary and eutectic silicon and by controlling the solidification parameters. In this paper, the effect of solidification rate and melt treatment on the evolution of microstructure in hypereutectic Al–Si alloys are reviewed. Different types of primary silicon morphology and the conditions for its nucleation and growth are explained. The paper discusses the effect of refinement/modification treatments on the microstructure and properties of the hypereutectic Al-Si alloy. The importance and effect of processing variables and phosphorus refinement on the silicon morphology and wear properties of the alloy is highlighted.     

Effect of Co on Microstructure and Interfacial Properties of FeBased Laser Cladding

The coatings consisting of Fe064Ni036 dendrites as matrix and (Fe,Cr)7(C,B)3 interdendritic compounds as reinforcement were fabricated on the medium steel substrate by laser cladding using the Febased powders with different Co content, and Co is uniformly dissolved in the coatings. Compared with the coatings containing 1% and 5% Co, the coating containing 3% Co increases in the area fraction of the interdendritic region by about 5%, in the microhardness nearby the interface by about HV 55 and in the interfacial bond strength by about 30 MPa. The interface fracture morphology exhibits the tear appearance, which can be characterized as the ductile fracture.     

Comparison of the Effect of Ni,Mn, Fe,and Si Additives on the Microstructure and Phase Composition of Hypereutectic Aluminum–Calcium Alloys

Russian Journal of Non-Ferrous Metals - A comparative analysis of the phase composition and morphology of primary crystals in hypereutectic alloys of the Al–Ca–Ni–X system (where...     

Research Advance on Magnetocaloric Effect of La-Fe-M(Al, Si) Compounds

Inviewofenergysavingandenvironmentalpro tection ,magneticrefrigerationnearroomtemperaturehasastrongimpactonconventionalgascompressiontechnology .However ,coolingefficiencyofthesystemformagneticrefrigerationismainlydecidedbythemagnitudeofmagnetocaloriceffectformagneticrefrig eratingmaterialsinthesystemunderacertainmagnet icfieldchange .Therefore ,developmentofnewrefrig eratingmaterialswithgreatmagnetocaloriceffectnearroomtemperatureisespeciallyimportant .Therearetwoparameterswhichareusedtochara…     

Effect of praseodymium and cobalt substitution on magnetic properties and structures in La(Fe_(1–x)Si_x)_(13) compounds

Magnetic properties and structures in La1-zPrz(Fe0.895–xCoxSi0.105)13 (x=0.07, 0.08; z=0, 0.2, 0.4) compounds were investigated. When Pr and Co substituted for La and Fe, the Curie temperature of the compounds was adjusted to around room temperature. The magnetic phase transition was driven from first-order to second-order due to Co substitution. As a second-order phase transition material, the MCE of La0.6Pr0.4(Fe0.825Co0.07Si0.105)13, whose relative cooling power was 175 J/kg under a field change of 2 T, ...     

The Effect of Bridge Geometry on Microstructure and Texture Evolution During Porthole Die Extrusion of an Al–Mg–Si–Mn–Cr Alloy

Porthole die extrusion is used to produce complex hollow aluminum cross-sections for automotive applications. In a porthole die, the material is first divided into multiple streams which are separated by a bridge, before rejoining in the weld chamber and finally passing through the die orifice. The rejoining of the material in the weld chamber produces lines known as weld lines in the final extruded product. The microstructure along the weld line and its associated quality are strongly influenced by the thermal-mechanical history the material experiences as it passes through the portholes, the weld chamber, and the die orifice, which can be altered by die design and, in particular, the bridge geometry. To study the influence of bridge geometry on weld line microstructure and final quality, a series of porthole die extrusion experiments was conducted using an Al–Mg–Si–Mn–Cr alloy and two different types of bridge geometry (streamlined and flat). The experimental results showed that bridge geometry had a significant effect on the local microstructure and crystallographic texture at the weld line. Specifically, EBSD analysis indicated that the weld line texture associated with a streamlined bridge geometry consisted of a deformation texture (mainly the copper component), while the local texture produced by a flat bridge was a recrystallization texture consisting of Cube, Goss, and Cube_RD texture components. Simulation of the extrusion process, using DEFORM 3D, indicated that the weld line produced using a flat bridge experienced a slightly higher temperature, but much higher equivalent strains than the streamlined case. Material away from the weld line was very similar for both cases, indicating that the effect of the die bridge geometry is localized to the region close to the weld line.

     

Influence of Magnetic Heat Treatment and Compressive Stress on Jump Effect of Magnetostriction of Tb0.3Dy0.7Fe1.95 Alloy

Influence of Magnetic Heat Treatment and Compressive Stress on Jump Effect of Magnetostriction of Tb_(0.3)Dy_(0.7)Fe_(1.95) Alloy     

Effect of Cooling Rate and Neodymium Addition on Beta Intermetallic Phase of Al–Fe–Si Ternary System

Aluminium silicon alloys are widely used in automotive industry and other structural application. However, the presence of high content of iron element in Al–Si alloys lead to precipitation of beta intermetallic phase that has a detrimental effect on mechanical properties. Reducing the adverse effects of β-Al₉Fe₂Si₂ precipitates can be achieved by altering their morphology by adding element modifier and increasing solidification cooling rate. In this present work, simultaneous thermal analysis was used to study the effect of cooling rate (5, 10 and 30 °C min^?1) on beta phase formation in Al–7Si–1Fe alloy added with neodymium at 0.3, 0.6 and 1 wt%. The beta phase precipitates were then characterized using optical microscopy and scanning electron microscopy equipped with EDS. Image analysis results showed the reduction in size of beta intermetallic phase as a result of the rare earth addition. Further analysis also showed the refinement of eutectic silicon.     

Effect of Multiple Alloying Elements on Microstructure and Magnetic Properties of Nanocomposite Nd2Fe14B／α-Fe Magnets

TheappearanceofnanocompositemagnetsbroketheremanencelimitpredictedbyStoner Wolhfarthmodethattheremanenceofisotropicmagnetwouldnotexceedhalfofitssaturationmagnetization[1] .Accord ingtoSkomski′scalculation[2 ] ,highmaximalenergyproduct (BH) maxof 80 0kJ·m-3 couldbeachievedinNd2 Fe14 B α FenanocompositewhentheaveragegrainsizeofNd2 Fe14 Bisrefinedtoabout 2 0nmandthatofα Fetoabout 10nm ,becauseoftheeffectofrema nenceenhancement (Mr Ms >0 .5 ) .Unfortunately ,thereported (BH) max(185kJ·…     

Magnetic Properties and Molecular Field Analysis of （ Ce, Nd） 2 （Fe, Si, Mn） 17 Compounds

The temperature-dependent magnetization of the ( Ce, Nd) 2 (Fe, Si, Mn) 17 intermetallic compounds were measured and analyzed by molecular field theory (MFr). The relationship between Tc and the intrasublattice coupling interactions was discussed. The two-sublattice MFT model can well describe the temperature dependence of the magnetization for all the compounds investigated. Ce ion in (Ce, Nd)2Fel7 compounds does not simply dilute the magnetic structure, but is likely present in a mixed-valence state. The substitution of Si for Fe strongly raises Tc and the mean Fe moment remains unchanged for Ce2(Si, Fe)17 compounds, and the 3d exchange coupling constant JFF increases linearly. Mn decreases Tc of Nd2(Mn, Fe)17 compound by reducing JFF。     

Effect of Mn Content on Microstructure and Mechanical Properties of Fe–Mn–Cr–C High-Manganese Steels Produced Using Laser-Directed Energy Deposition

The microstructure and mechanical properties of high-manganese steel (HMnS) fabricated using laser-directed energy deposition (LDED) with Fe–Mn–4Cr–0.4C alloys with Mn contents of 13, 18.5, and 24 wt% are investigated. Additionally, the effect of annealing heat treatment on the microstructure and mechanical properties of the deposited HMnS is examined. Regardless of the manganese content, the deposited HMnS exhibits a fine microstructure without any defects (cracks or voids) and a strong fibrous texture along the <001>//building direction of the primary austenite phase. In addition, regardless of the manganese content, the grain size increases during annealing heat treatment, and the hardness decreases as the annealing temperature increases. The strength tends to decrease as the Mn content increases in the as-built state. In addition, regardless of the Mn content, the yield strength and ultimate tensile strength tend to decrease owing to the effect of annealing heat treatment. Although the maximum elongation of 18.5Mn and 24Mn does not change significantly upon heat treatment, the maximum elongation of 13Mn is greatly reduced by annealing. The deformation behavior of HMnS is characterized by transformation-induced plasticity (TRIP) for 13Mn and both TRIP and twinning-induced plasticity for 18.5Mn and 24Mn.     

Magnetic Transition of La0.8Sr0.2Mn1-xCoxO3（x =0, 0.3, 0.5, 1.0）

A series of rare earth compound oxides with the formula of La0.8Sr0.2Mn1-xCoxO3（ were prepared by the method of citric acid. Structures, figures and magnetic properties of the x=0.0, 0.3, 0.5, 1.0） samples were analyzed by means of XRD, SEM and SQUID. Experiment results prove that all the samples are hexagonal, but their figures and magnetic properties are different. La0.8Sr0.2MnO3 is ferromagnetic. La0.8Sr0.2Mn0.7CO0.3O3 and La0.8Sr0.2Mn0.5Co0.5O3 are ferrimagnetic. La0.8Sr0.2CoO3 is antiferromagnetic. SEM results indicate that the structure of the first three are three-dimensional reticulations which are made up of some small ellipsoids which link up at the head and the end. The fourth sample looks like some dispersed small balls.