Effect of gadolinium on the properties of Pr–Dy–Fe–Co–B materials

Sintered (Pr_1–x–y Dy _x Gd _y )_13–14(Fe_1–z Co _z )_balB_6–7 materials (x = 0.18–0.58, y = 0.05–0.33, z = 0.2–0.36) have been studied. The magnetic moments of gadolinium ions and those of the sublattice formed by Fe and Co ions are shown to be ordered antiferromagnetically. It is noted that an increase in the content of gadolinium, which substitutes for dysprosium, leads to an increase in residual induction B _r , a decrease in coercive force H _cJ , and an increase in the absolute value of the temperature coefficient of induction. The opposite effect takes place in the case of substitution of gadolinium for praseodymium in materials with a fixed dysprosium content.     

Magnetic Structure and Nanomechanical Properties of Sintered Permanent Magnets Nd–Dy–Fe–B USC-20L

Russian Journal of Non-Ferrous Metals - Using scanning electron microscopy (EDS analysis), magnetic force microscopy, and nanoindentation, a metallographic study of the magnetic structure and...     

Effect of Impurities on the Phase Composition and Properties of a New Alloy of the Al–Y–Er–Zr–Sc System

Metallurgist - A comparative study is provided for the effect of Si and Fe impurities in relation to their concentration in the structure, phase composition, and mechanical properties of alloy...     

Effect of cobalt on the oxidation resistance of Pr(Nd)–Dy–Fe–Co–B materials

The effect of cobalt on the oxidation resistance of (Nd_0.85Dy_0.15)_16.4(Fe_0.89Co_0.11)_74.4Ti_1.3B_7.9 and (Pr_0.56Dy_0.39Sm_0.05)_14.5(Fe_0.75Co_0.25)_78.8B_6.7 alloys has been studied. The storage of magnet blanks made from these alloy in air for 200 h does not affect the magnetic properties of the sintered magnets owing to the presence of the phases (Pr, Dy)(Fe, Co)₂, (Pr, Dy)(Fe, Co)₂B₂, (Pr, Dy)(Fe, Co)₄B, (Pr, Dy)(Fe, Co)₃B₂, and (Pr, Dy)(Fe, Co)₃, which are resistant to oxidation and ensure liquid-phase sintering of magnets. After 200-h exposure to air, oxidation of the blanks takes place, the rate of which decreases by more than two times at the expense of an increase in the cobalt content in the alloy.     

Combined Effect of Calcium and Silicon on the Phase Composition and Structure of Al–10%Mg Alloy

Phase transformations in the Al–Ca–Mg–Si system in the region of aluminum–magnesium alloys are investigated using the Thermo-Calc program. The liquidus projection of the quaternary system is constructed with a Mg content of 10% and it is shown that phases Al4Ca, Mg₂Si, and Al₂CaSi₂ can crystallize (in addition to the aluminum solid solution (Al)) depending on the calcium and silicon concentrations. The crystallization character of quaternary alloys is investigated with the help of a polythermal cross section calculated at concentrations of 10% Mg and 84% Al. Based on the analysis of phase transformations occurring in alloys of this section, the presence of the Al–Al₂CaSi₂–Mg₂Si quasi-ternary section in the Al–Ca–Mg–Si system was assumed. Three experimental alloys were considered from a quantitative analysis of the phase composition, notably, Al–10% Ca–10% Mg–2% Si, Al–4% Ca–10% Mg–2% Si, and Al–3% Ca–10% Mg–1% Si. Metallographic investigations and electron-probe microanalysis were performed using a TESCAN Vega 3 scanning electron microscope. Critical temperatures are determined using a DSC Setaram Setsys Evolution differential calorimeter. The experimental results agree well with the calculated data; in particular, a peak at t ~ 450°C is revealed for all alloys in curves of the nonequilibrium solidus and invariant eutectic reaction L → (Al) + Al₄Ca + Mg₂Si + Al₃Mg₂. It is established that the structure of the Al–3% Ca–10% Mg–1% Si alloy is closest to the eutectic alloy. It is no worse that the AMg10 alloy in regards to density and corrosion resistance and even surpasses it in hardness, which allows us to consider this alloy as the basis for the development of a new cast material: “natural composites.”     

The Influence of Synthesis Conditions on the Phase Composition,Structure, and Properties of the High-Entropy Ti–Cr–Fe–Ni–Cu Alloy

Powder Metallurgy and Metal Ceramics - The influence of production conditions on the structure, phase composition, and properties of the high-entropy Ti–Cr–Fe–Ni–Cu alloy...     

Effect of Microadditional Cerium on Annealing Embrittlement of Fe－B－Si Amorphous Alloy

ＥｆｆｅｃｔｏｆＭｉｃｒｏａｄｄｉｔｉｏｎａｌＣｅｒｉｕｍｏｎＡｎｎｅａｌｉｎｇＥｍｂｒｉｔｔｌｅｍｅｎｔｏｆＦｅ－Ｂ－ＳｉＡｍｏｒｐｈｏｕｓＡｌｌｏｙ￥ＣａｏＸｉｎｇｇｕｏ；ＣｈｅＸｉａｏｚｈｏｕ（ＤｅｐａｒｔｍｅｎｔｏｆｍａｔｅｒｉａｌｓＥｎｇｉ...     

Effect of Melting Process on the Microstructure and Mechanical Properties of Fe–7 wt% Al Alloy

This article presents the effect of melting process on chemical composition, microstructure and mechanical properties of Fe–7 wt% Al alloy. The alloy ingot was prepared by air induction melting (AIM), air induction melting with flux cover (AIMFC) and vacuum induction melting (VIM) and cast into 50 mm diameter split cast iron mould. These cast ingots were hot-forged and hot-rolled at 1,373 K to 2 mm thick sheet. Hot-rolled alloys were characterized with respect to chemical composition, microstructure and mechanical properties. Ingots produced by AIM, AIMFC and VIM were free from gas porosity, however AIM ingots exhibited higher concentration of hydrogen as compared to AIMFC and VIM. The recovery of aluminium as well as reduction of oxygen during AIM is very poor as compared to AIMFC and VIM. AIMFC ingots exhibit low level of sulphur as compared to AIM and VIM ingots. The alloys produced by AIMFC and VIM exhibited superior tensile ductility compared to the alloys produced by AIM. The tensile properties of alloys produced by AIMFC are comparable to the alloys produced by VIM.     

Effect of Bismuth and Lead on the Phase Composition and Structure of the Al–5% Si–4% Cu–4% Sn Alloy

Russian Journal of Non-Ferrous Metals - This article is devoted to the topical problem of developing antifriction aluminum alloys economically alloyed with low-melting metals. It was found in...     

Effect of Annealing Temperature and Time on Martensitic Transformation Temperatures and Mechanical Properties of the Ti–50.7 at % Ni Shape Memory Alloy

Russian Journal of Non-Ferrous Metals - The influence of temperature and time of recrystallization annealing on the characteristic temperatures of martensitic transformation and mechanical...     

Solidification Behavior of Laser Melting Layer of Nd15Fe77B8 Sintered Magnets and Its Microstructures Evolution

To research the solidification behavior and microstructures of a laser remelting/solidification layer on anisotropic Nd15Fe77B8 sintered magnets with their magnetization direction parallel to X, Y, Z-axis respectively, their surfaces (parallel to XOY plane) were scanned by 5 kW Roffin-Sinar 850 type of CO2 laser along Y axis. The rapid solidification of the molten alloy in the layer results in three distinct zones. The transition zone close to the unmolten portion of a magnet (substrate), consists of the columnar Nd2Fe14B phase (matrix), the 10.0%～15.1% dendrite primary iron phase dispersing in the matrix, and the Nd-rich phase along Nd2Fe14B grain boundaries. The columnar crystal zone in the middle of the layer consists of the long columnar Nd2Fe14B grains and their grain boundary Nd-rich phase. And the dendrite crystal zone near the free surface of the layer consists of dendrite Nd2Fe14B grains and their grain boundary Nd-rich phase. When the laser scanning velocity is lower, the growing direction of the microstructures in the layer tends to the laser scanning direction step by step. When the velocity is not lower than 25 mm · s-1, the laser remelting/solidification layer thins and the columnar crystal zone comprises almost the whole layer. Under this condition, on the substrate with its magnetization direction along X or Y-axis respectively, the columnar Nd2Fe14B grains in the layer grow in the direction of Z-axis (that is their long-axis along Z-axis), their alignment of the easy magnetization axis [001] is parallel to the magnetization direction of the substrate correspondingly; but on the substrate with its magnetization direction along Z-axis, the columnar Nd2Fe14B grains in the transition zone grow at an angle of 30°～50° between Z-axis and their long-axis. And the columnar Nd2Fe14B grains in the columnar crystal zone gradually tend to the Z-axis,and their easy magnetization axis [001] arrange in the range of 0°～360° of the plane perpendicular to their long-axis.     

Influence of Molybdenum and Rhenium Dopants on the Structure and Properties of NiAl–Cr–Co Cast Alloy

Russian Journal of Non-Ferrous Metals - Centrifugal SHS casting has been used for the production of NiAl–Cr–Co–X alloys, where X = 2.5–15.0 wt % Mo and up to 1.5 wt % Re....     

Pore Formation and Its Effect on Mechanical Properties in W—Ni—Fe Heavy Alloy

Abstract

W–Ni–Fe heavy alloy tensile specimens were sintered at 1450°C for various times up to 44h. The W content varied between 90 and 96 wt-%, and the Ni to Fe weight ratio was 1:1. The specimens are fully densified after 15 min to 1 h of sintering and show high strength and ductility. During the tension test, cracks are formed at the interface between tungsten grains when the grain deformation reaches critical levels. The number of these intergranular cracks increases with deformation until the specimens fracture. When the specimens are over-sintered for 4 and 8 h, large irregular pores are formed with a sharp decrease of strength and ductility. Upon further sintering, the porosity decreases again with a recovery of the mechanical properties. The results demonstrate that small amounts of porosity, even 1 or 2%, can cause drastic reduction of the mechanical properties in tungsten heavy alloys.     

Study of the Effect of Hot－pressing Techniques on the Magnetic Properties of Pr－Fe－B Alloys

ＳｔｕｄｙｏｆｔｈｅＥｆｆｅｃｔｏｆＨｏｔ－ｐｒｅｓｓｉｎｇＴｅｃｈｎｉｑｕｅｓｏｎｔｈｅＭａｇｎｅｔｉｃＰｒｏｐｅｒｔｉｅｓｏｆＰｒ－Ｆｅ－ＢＡｌｌｏｙｓ￥ＹａｎｇＸｉａｎｊｉｎ（杨贤金），ＹａｏＪｉａｘｉｎ（姚家鑫），ＺｈａｏＮａｉｑｉｎ（赵乃勤...     

Effect of Boron and Cerium on Microstructures and Properties of Cu-Fe-P Alloy

The effects of B and Ce on the removal of inclusions, microstructures, and properties of Cu-Fe-P alloys were studied. Certain impurity elements and the microstructures, mechanical properties, and conductivity of four experimental alloys, Cu-0.22Fe-0.06P, Cu-0.22Fe-0.06P-0.05Ce, Cu-0.22Fe-0.06P-0.02B, and Cu-0.22Fe-0.06P-0.05Ce-0. 02B （ %, mass fraction）, were tested and analyzed. Results show that on one hand, B and Ce have a remarkable function of removing S, Pb, and Bi from copper alloys ; on the other hand, the recrystallization temperature of the Cu-Fe-P alloy is considerably increased by adding trace B and Ce, resulting in the combined strengthening effect of precipitation hardening and cold work hardening after cold working and aging, while the negative effect of B and Ce on conductivity is slight. Therefore, a good combination of high strength and conductivity is achieved.     

Effect of Friction Stir Processing on Microstructure and Mechanical Properties of a Cast-Magnesium–Rare Earth Alloy

Single-pass friction stir processing (FSP) was used to increase the mechanical properties of a cast Mg-Zn-Zr-rare earth (RE) alloy, Elektron 21. A fine grain size was achieved through intense plastic deformation and the control of heat input during processing. The effects of processing and heat treatment on the mechanical and microstructural properties were evaluated. An aging treatment of 16 hours at 200 °C resulted in a 0.2 pct proof stress of 275 MPa in the FSP material, a 61 pct improvement over the cast + T6 condition.