Exchange-coupling between soft- and hard-magnetic phases plays an important role in the engineering of novel magnetic materials. To achieve exchange coupling, a two-phase microstructure is necessary. This interface effect further enhanced if both phase dimensions are reduced to nanometer scale. At same time, it challenging obtain large sample dimensions. In this study, powder blends ball-milled Fe-SmCo5 consolidated deformed by high-pressure torsion (HPT), as technique allows us produce bulk...

High-pressure torsion (HPT), a technique of severe plastic deformation (SPD), is shown as promising processing method for exchange-spring magnetic materials in bulk form. Powder mixtures Fe and SmCo$_{5}$ are consolidated deformed by HPT exhibiting sample dimensions several millimetres, being essential bulky applications. The structural evolution during Fe-SmCo$_{5}$ compounds at room- elevated- temperatures chemical compositions consisting 87, 47, 24 10 wt.% studied microstructurally...

Bulk composites using powder blends of Mn and Bi with equal atomic ratios are consolidated severely deformed by high-pressure torsion (HPT). Subsequent annealing treatments lead to the formation ferromagnetic rare-earth free hard magnetic α-MnBi phase. The initial phase is studied in-situ high-energy XRD experiments showing a beneficial influence HPT-deformation on amount α-MnBi. nucleation sites strongly increased, thus volumetric content exceeds 50 vol%. A lower HPT-pressure 2 GPa found be...

The capability of high-pressure torsion on the preparation supersaturated solid solutions, consisting Cu-14Fe (wt.%), is studied. From microstructural investigations a steady state obtained with nanocrystalline grains. as-deformed analyzed atom probe tomography, revealing an enhanced solubility and presence Fe-rich particles. DC-hysteresis loop shows suppressed long range interactions in evolves towards typical bulk hysteresis when annealed at 500∘ C. AC-susceptometry measurements reveal...

Initial powder mixtures of Cu, Fe and Co are exposed to severe plastic deformation by high-pressure torsion prepare solid solutions. A broad range compositions is investigated, whereas this study aims at the synthesis soft magnetic materials therefore formation a homogeneous nanocrystalline microstructure. For intermediate ferromagnetic contents, room temperature yields single-phase supersaturated higher two consecutive steps different temperatures yield desired Depending on Co-to-Fe-ratio,...

Samples consisting of one ferromagnetic and diamagnetic component which are immiscible at the thermodynamic equilibrium (Co-Cu, Fe-Cu, Fe-Ag) processed by high-pressure torsion various compositions. The received microstructures investigated electron microscopy synchrotron X-ray diffraction, showing a microstructural saturation. Results gained from investigations correlated to magnetometry data. Co-Cu samples show mainly behavior decrease in coercivity with increasing Co-content. saturation...

Bulk nanocrystalline materials of small and medium ferromagnetic content were produced using severe plastic deformation by high-pressure torsion at roomtemperature. Giant magnetoresistive behavior was found for as deformed materials, which further improved adjusting the microstructure with thermal treatments. The adequate range annealing temperatures assessed in-situ synchrotron diffraction measurements. Thermally treated CuCo show larger giant magnetoresistance after 1 h 300C, while CuFe...

Bulk metallic samples were synthesized from different binary powder mixtures consisting of elemental Cu, Co, and Fe using severe plastic deformation. Small particles the ferromagnetic phase originate in conductive Cu phase, either by incomplete dissolution or segregation phenomena during deformation process. These small are known to give rise granular giant magnetoresistance. Taking advantage simple production process, it is possible perform a systematic study on influence processing...

In this study, a preparation route of Co–Cu alloys with soft magnetic properties by high-pressure torsion deformation is introduced. Nanocrystalline, supersaturated single-phase microstructures are obtained after alloys, which prepared from an initial powder mixture Co-contents above 70 wt.%. Isochronal annealing treatments up to 400 °C further reveal remarkable microstructural stability. Only at 600 °C, the phase decomposes into two fcc-phases. The coercivity, measured SQUID as function...

Nanocrystalline materials are well known for their beneficial mechanical and physical properties. However, it is of utmost importance to stabilize the microstructure at elevated temperatures broaden window application e.g. by pinning grain boundaries through impurities or oxides. CuCo alloys, severe plastically deformed using high-pressure torsion, were used investigate evolution oxides upon annealing. These investigations performed electron microscopy, synchrotron high-energy X-ray...

This work gives insights into processing and characterisation of bulk nanocrystalline FeCr materials. The investigated alloys, consisting 30, 50 70 at.% ferromagnetic Fe remaining anti-ferromagnetic Cr, are processed by arc melting subsequent severe plastic deformation high pressure torsion. physical similarities between elemental Cr in combination with the structure as-deformed necessitates advanced techniques for state: In-situ annealing synchrotron X-ray diffraction measurements as well...

Severe plastic deformation using high-pressure torsion of ternary Cu-based materials (CuFeCo and CuFeNi) was used to fabricate bulk samples with a nanocrystalline microstructure. The goal produce featuring the granular giant magnetoresistance effect, requiring interfaces between ferro- nonmagnetic materials. This magnetic effect found for both systems; adequate subsequent annealing had positive influence. as-deformed states, as well microstructural changes upon thermal treatments, were...

Co-Zr amorphous alloys exhibit soft magnetic properties, whereas the Co-rich crystalline phases in this alloy system displayed a hard behavior. In study, an initial two-phase composite with overall composition of 75 at.% Co and 25 Zr was processed by high-pressure torsion (HPT), effects severe plastic deformation subsequent thermal treatment on composite’s structural evolution its properties were investigated. HPT processing allowed us to achieve microstructure low coercivity as-deformed...

The changes of magnetic properties upon heat treatment a metastable supersaturated solid solution processed by severe plastic deformation are investigated in-situ AC-hysteresis measurements. Data analyzed in the framework dynamic loss theory, with correlative investigations microstructural properties. evolution hysteresis annealing points out that single-phase remains stable up to 400{\deg}C, then hindering domain wall motion sets at this temperature. At 600{\deg}C, multi phase...

The processing of binary alloys consisting ferromagnetic Fe and antiferromagnetic Cr by severe plastic deformation (SPD) with different chemical compositions has been investigated. Although the phase diagram exhibits a large gap in thermodynamical equilibrium at lower temperatures, it is shown that techniques based on SPD help to overcome common limits. Different routes including initial ball milling (BM) arc melting (AM) concatenation annealing treatments prior high-pressure torsion (HPT)...

Mixtures of Fe and Cu powders are cold-compacted subsequently deformed with severe plastic deformation by high-pressure torsion, leading to bulk samples. The dilution in the matrix is investigated SQUID-magnetometry, whereas magnetic properties change as a function Fe-content from frustrated regime thermal activated behaviour. correlated microstructure, synchrotron X-ray diffraction atom probe tomography. Annealing as-deformed states leads demixing grain growth, coercivity annealing...

Co-Zr amorphous alloys exhibit soft magnetic properties, whereas Co-rich crystalline phases in this alloy system display hard behaviour. In study, an initial two-phase composite with overall composition of 75 at.% Co and 25 Zr was processed by high pressure torsion (HPT) the effects severe plastic deformation subsequent thermal treatment on structural evolution its properties have been investigated. HPT processing allowed us to achieve microstructure as-deformed state low coercivity. To...

The paper describes the capability of magnetic softening a coarse-grained bulk material by severe deformation technique. Connecting microstructure with properties, coercive field decreases dramatically for grains smaller than exchange length. This makes investigation soft properties severely drawn pearlitic wires very interesting. With help starting two-phase microstructure, it is possible to substantially refine material, which allows nanocrystalline material. Compared initial, state,...

From microstructural investigations a steady state is obtained with nanocrystalline grains. The DC-hysteresis loop shows suppressed long range interactions in the as-deformed and evolves towards typical bulk hysteresis when annealed at 500°C. AC-susceptometry measurements of reveal presence superparamagnetic blocking peak, as well magnetic frustrated phase, whereas transition latter follows Almeida-Thouless line. that vanishes for annealing 250°C.

Co-Zr amorphous alloys exhibit soft magnetic properties, whereas Co-rich crystalline phases in this alloy system display hard behaviour. In study, an initial two-phase composite with overall composition of 75 at.% Co and 25 Zr was processed by high pressure torsion (HPT) the effects severe plastic deformation subsequent thermal treatment on structural evolution its properties have been investigated. HPT processing allowed us to achieve microstructure as-deformed state low coercivity. To...

Bulk composites using powder blends of Mn and Bi with equal atomic ratios are consolidated severely deformed by high-pressure torsion (HPT). Subsequent annealing treatments lead to the formation ferromagnetic rare-earth free hard magnetic α-MnBi phase. The initial phase is studied in-situ high-energy XRD experiments showing a beneficial influence HPT-deformation on amount α-MnBi. nucleation sites strongly increased, thus volumetric content exceeds 50 vol.%. A lower HPT-pressure 2 GPa found...