Composition-Induced Magnetic Transition in GdMn1-xTixSi Intermetallic Compounds for x = 0–1

Magnetic intermetallic compounds based on rare earth elements and 3d transition metals are widely investigated due to the functionality of their physical properties and their variety of possible applications. In this work, we investigated the features of the electronic structure and magnetic properties of ternary intermetallic compounds based on gadolinium GdMn1-xTixSi, in the framework of the DFT + U method. Analysis of the densities of electronic states and magnetic moments of ions in Ti-doped GdMnSi showed a significant change in the magnetic properties depending on the contents of Mn and Ti. Together with the magnetic moment, an increase in the density of electronic states at the Fermi energy was found in almost all GdMn1-xTixSi compositions, which may indicate a significant change in the transport properties of intermetallic compounds. Together with the expected Curie temperatures above 300 K, the revealed changes in the magnetic characteristics and electronic structure make the GdMn1-xTixSi intermetallic system promising for use in microelectronic applications.

Durability and activity of Co2YZ (Y = Mn or Fe, Z = Ga or Ge) Heusler alloy catalysts for dehydrogenation of 2-propanol

As a group of ternary intermetallic compounds, Heusler alloys (X2YZ) can be unique catalysts. Heusler alloys are suitable as a platform to reveal a common rule for the catalysis of...

Synthesis of Mg–Zn–Nd Master Alloy in Metallothermic Reduction of Neodymium from Fluoride–Chloride Melt

In the presented article, a differential thermal analysis was carried out and the temperatures of thermal effects were established that arise during the reduction of neodymium from a technological salt mixture KCl–NaCl–CaCl2–NdF3 with a magnesium–zinc alloy. The results of experimental studies on the reduction of neodymium from a fluoride–chloride melt in a shaft electric furnace at temperatures of 550, 600, 650, 700 °C are presented. In order to increase the degree of extraction of neodymium into the Mg–Zn–Nd master alloy, the study of the influence of technological parameters on the degree of extraction of neodymium was carried out. It was experimentally proven that when zinc is added to a reducing agent (magnesium), the degree of extraction of neodymium into the master alloy is 99.5–99.7%. The structure of the obtained master alloy samples, characterized by a uniform distribution of ternary intermetallic compounds (Mg3,4NdZn7) in the volume of a double magnesium–zinc eutectic, was studied by optical and electron microscopy.

Ternary Aluminides of a New Homologous Series—CePt2Al2 and CePt3Al3: Crystal Structures and Thermal Properties

In the process of studying the Ce–Pt–Al system, we identified CePt2Al2 and CePt3Al3, two new ternary intermetallic compounds. CePt2Al2 aluminide undergoes a structural phase transition from a low-temperature orthorhombic modification (of its own structure type, Cmme, a = 5.84138(2) Å, b = 6.39099(3) Å, c = 10.11611(5) Å) to a high-temperature tetragonal modification (CaBe2Ge2 type, P4/nmm, a = 4.3637(9) Å, c = 10.0925(14) Å) at 280(1) °C. CePt3Al3 crystallizes with a new type of structure (Cmme, a = 6.36548(6) Å, b = 5.78301(6) Å, c = 13.36245(19) Å) built of structural units of low-temperature orthorhombic CePt2Al2-type and CsCl-type.

Exhibition of veiled features in diffusion bonding of titanium alloy and stainless steel via copper

An investigation was carried out to know the extent of influence of bonding-time on the interface structure and mechanical properties of diffusion bonding (DB) of TiA|Cu|SS. DB of Ti6Al4V (TiA) and 304 stainless steel (SS) using pure copper (Cu) of 200-μm thickness were processed in vacuum using 4-MPa bonding-pressure at 1123 K from 15 to 120 min in steps of 15 min. Preparation of DB was not possible when bonding-time was less than 60 min as the bonding at Cu|SS interface was unsuccessful in spite of effective bonding at TiA|Cu interface; however, successful DB were produced when the bonding-time was 60 min and beyond. DB processed for 60 and 75 min (classified as shorter bonding-time interval) showed distinctive characteristics (structural, mechanical, and fractural) as compared to the DB processed for 90, 105, and 120 min (classified as longer bonding-time interval). DB processed for 60 and 75 min exhibited layer-wise Cu–Ti-based intermetallics at TiA|Cu interface, whereas Cu|SS interface was completely free from reaction products. The layer-wise structure of Cu–Ti-based intermetallics were not observed at TiA|Cu interface in the DB processed for longer bonding-time; however, the Cu|SS interface had layer-wise ternary intermetallic compounds (T1, T2, and T3) of Cu–Fe–Ti-based along with σ phase depending upon the bonding-time chosen. Diffusivity of Ti-atoms in Cu-layer (DTi in Cu-layer) was much greater than the diffusivity of Fe-atoms in Cu-layer (DFe in Cu-layer). Ti-atoms reached Cu|SS interface but Fe-atoms were unable to reach TiA|Cu interface. It was observed that DB fractured at Cu|SS interface when processed for shorter bonding-time interval, whereas the DB processed for longer bonding-time interval fractured apparently at the middle of Cu-foil region predominantly due to the existence of brittle Cu–Fe–Ti-based intermetallics.

Thermodynamic Calculation of Phase Equilibria in the Mn-RE (RE=Nd, Gd, Dy) Binary Systems

Ternary intermetallic compounds with rare earth elements and transition metals in the RE-Mn-X (X=Si, Ge, Sn etc.) ternary systems show interesting magnetic properties. As key sub-binary systems of the RE-Mn-X (X=Si, Ge, Sn etc.) ternary systems, the information of phase equilibria and thermodynamic properties of the Mn-RE (RE=Nd, Gd, Dy) binary systems are indispensable to explore the RE-Mn-X (X=Si, Ge, Sn etc.) alloys with better magnetic properties. In this work, the experimental data of phase equilibria and thermodynamic properties of the Mn-RE (RE=Nd, Gd, Dy) binary systems in the published literature were reviewed. Based on the available experimental information, thermodynamic calculation of phase equilibria of the Mn-RE (RE=Nd, Gd, Dy) binary systems was performed using the CALPHAD method. As a result, further experimental investigation and thermodynamic optimization would be still necessary in order to develop the self-consistent and compatible thermodynamic database of the RE-Mn-based alloy systems.