Mn Cr System Research Articles

Особливості структуроутворення в економнолегованих хромомарганцевих залізовуглецевих сплавах для гірничо-металургійного обладнання

It was established that in cast chromium-manganese alloys of the transition class Fe–C–Mn–Cr system (carbon content no more than 2.2%) with a certain combination of Mn and Cr, the formation of crystals of highly hard carbide Me7C3 is possible. The relationship between the phase-concentration parameters and the structure formation of alloys of the Fe–C–Mn–Cr system was studied, the analysis of the relationship between the phase-concentration parameters, structure formation and properties was carried out on the compositions of the Fe–C–Mn and Fe–C– Mn–Cr with 1.5-2.1% C, with a variable content of Mn, Cr and additives of other alloying elements - Si and Ni at the level of impurities. A phase-concentration diagram of the crystallization of the alloys of this system was constructed, delimiting the regions of crystallization P → γ-Fe, P → γ-Fe + Me3C and P →(γ -Fe + Me7C3) + (γ-Fe + Me3C). It is shown that economically alloyed chromium-manganese alloys of the Fe–Mn–Cr–C system with eutectics based on Me7C3 carbide are characterized by a high level of shock-abrasive wear resistance, and the results of the conducted studies indicate the prospects of using economically alloyed chromium-manganese alloys and can be recommended for further research and use as wear-resistant materials for the manufacture of parts of replaceable metallurgical equipment, which are operated in severe conditions of abrasive and shock-abrasive wear. Keywords: phase-concentration diagram, microstructure, Me7C3 carbide, impact-abrasive wear resistance, chromium-manganese alloys

Study of the relationship among total oxygen, inclusions and fatigue properties of gear steel

In order to control non-metallic inclusions and improve fatigue performance of gear steel, the relationship among total oxygen, inclusion size and fatigue properties of gear steel was investigated. In the work, Mn–Cr system gear steels with different total oxygen contents were selected as the research objects. Inclusions and fatigue properties of gear steels with different total oxygen contents were studied by using traditional metallographic method, extreme value method and fatigue test. The experimental results demonstrates that with the decrease of total oxygen content（i.e., 0.0013%→0.0010%→0.0005%）, the number of small-size oxide inclusions in the range of 5–10 μm decreases greatly, whereas the number of large-size oxide inclusions over 10 μm has relatively little change. Meanwhile, it is found that the change of total oxygen content in different ranges has different influences on the size of maximum size oxide inclusion and fatigue properties. Reducing the total oxygen content of gear steel from 0.0013% to 0.0010% decreases the inclusion size of maximum oxide inclusion and improves fatigue resistance of materials, but these benefits do not extend to a total oxygen level of 0.0005%. Accordingly, we can conclude that no evident linear correlation exists between total oxygen content and maximum inclusion size or between the total oxygen content and the fatigue performance.

53Mn-53Cr systematics of sphalerite in enstatite chondrites

We investigated the 53Mn-53Cr isotopic composition of a suite of enstatite chondrites by in situ analyses of various mineral phases with the Cameca IMS 1280-HR ion probe at Heidelberg, Germany, and a Cameca NanoSIMS at Paris, France. Only in sphalerite we found anomalies in 53Cr/52Cr-ratios correlating with 55Mn/52Cr which are due to decay of short-lived 53Mn (t1/2 = 3.7 Ma). A sphalerite in the EH-impact melt LAP 02225 showed the largest excess of 53Cr, with 53Cr/52Cr-ratios ranging up to 2.2. The calculated initial 53Mn/55Mn-ratios are within the range of previous Mn-Cr studies. We observed a spatial variation within a large sphalerite in LAP 02225, translating in distinct initial 53Mn/55Mn values. In case of the EL3 chondrite MAC 88136 the initial 53Mn/55Mn derived for one sphalerite is at the lower end of previously reported values and may reflect a variable influence of alteration-induced exchange of common Cr. This is supported by the total reset of the 53Cr/52Cr-ratio in another sphalerite in contact with an alteration vein irrespective of high Mn/Cr-ratios. Our observed initial 53Mn/55Mn-ratios of Sahara 97158, Indarch and EET 96135 correspond to the I-Xe systematics and hence, show that sphalerites can preserve reasonable age information. For Indarch however, if compared with other initial 53Mn/55Mn values from literature, a considerable scatter is obvious. This clearly demonstrates that the Mn-Cr system in sphalerite can be disturbed by various, still poorly investigated, processes (e.g., by thermal events, weathering, diffusion-controlled remobilization). Future application of Mn-Cr dating to sphalerite in enstatite chondrites thus requires a better understanding of how such processes influence the Mn-Cr systematics and demands for tools to identify the undoubtly present sphalerites carrying a true chronologic information.

Chronological constraints on the thermal evolution of ordinary chondrite parent bodies from the 53Mn-53Cr system

The 53Mn-53Cr isotope systematics in ordinary chondrites constrains the accretion and thermal history of their parent bodies. Mineralogical observations and olivine-spinel geothermometry suggest that chromite in ordinary chondrites formed during prograde thermal metamorphism with the amount of chromite increasing with petrologic grades in type 3 to type 6 ordinary chondrites. Assuming a chondritic evolution of the respective parent bodies, 53Cr/52Cr model ages for chromite range from 3.99-0.79+0.93 to 11.1-2.8+6.0 Ma after the formation of calcium-aluminium-rich inclusions (CAIs). Chromite and silicate-metal-sulphide isochrons define an age range from 2.78-0.50+0.55 to 15.4-1.6+2.4 Ma. Both chromite model ages and isochron ages correlate with the petrological grade of the samples, which is consistent with an onion-shell structure of the chondrite parent bodies. The study shows that unlike the isochron ages, which are prone to impact-related disturbances or partial re-equilibration during cooling from high temperatures, the chromite model ages are not easily affected by thermal metamorphism or later events and yield robust mineral growth ages. The results are consistent with a homogenous distribution of 53Mn and an initial canonical 53Mn/55Mn = 6.28 × 10−6. The estimated closure temperatures for the Mn-Cr system in chromites range from ~760 °C for type 6 to ~540–620 °C for type 3 ordinary chondrites. The high closure temperatures estimated for type 3 and type 6 ordinary chondrites imply that the chromite ages correspond to the peak metamorphic temperature reached during the thermal history of the chondrite parent bodies. The oldest chromite model age obtained for type 3 samples along with the established Al-Mg chondrule formation ages constrain the accretion of the parent bodies to >2.1 Ma after CAI formation, implying that planetesimal accretion immediately followed chondrule formation.

Strategies to increase austenite FCC relative phase stability in High-Mn steels

Several strategies to increase the FCC austenite stability compared to BCC and HCP martensites have been tested and are discussed. The relative stability of the different phases was analyzed by studying the effects of: a) grain size, b) antiferromagnetic ordering of the austenite, c) thermal cycling through the FCC-HCP transition, d) plastic deformation of the austenite and e) combined effects. As a first step, the effect of decreasing the grain size was analyzed in Fe–Mn alloys for Mn contents smaller than 18 wt.%, where BCC and HCP martensites compete in stability. Formation of the BCC phase is inhibited for 15 wt.% and 17 wt.% of Mn for grain sizes smaller than 2 μm. This enabled, for the first time at these compositions, the measurement of the Néel temperature of the austenite using specific heat and magnetic measurements. A comparison of the obtained transition temperatures with accepted models is discussed. The effect of modifying the grain size on the FCC-HCP transition temperatures was also analyzed for 15 wt.% and 17 wt.% Mn contents showing a complete HCP inhibition for grain sizes smaller than 200 nm. A nucleation model for the HCP martensite is considered which includes an additional resistance to the transformation term depending on the austenitic grain size. Additional combined effects on the FCC stabilization are discussed like the interaction between the antiferromagnetic ordering and the introduction of defects by thermal cycling through the martensitic transformation. The analysis can be easily applied to systems with a larger number of components. Results obtained in the Fe–Mn–Cr system are also presented.

A Short Review on the Effect of Cr on the fcc–hcp Phase Transition in Fe–Mn-Based Alloys

The effect of Cr on the fcc–hcp martensitic transformation in the Fe–Mn–Cr system has been discussed considering different aspects: (a) the relative phase stabilities, (b) the magnetic order of the fcc phase, (c) the structural parameters and volume change between fcc and hcp, (d) the driving force of the martensitic transformation and relevant thermodynamics quantities, (e) the thermal cycling behavior, and (f) the pseudoelastic effect. Particularly, in this work it has been found that when Cr content increases, the effect of cycling on the energy barrier decreases. This may be explained by a small volume change, which could lead to a slighter introduction of plastic deformation during thermal cycling through the martensitic transition.

Progressive Transformation between Two Magnetic Ground States for One Crystal Structure of a Chiral Molecular Magnet.

We report the exceptional observation of two different magnetic ground states (MGS), spin glass (SG, T(B) = 7 K) and ferrimagnet (FI, T(C) = 18 K), for one crystal structure of [{Mn(II)(D/L-NH2ala)}3{Mn(III)(CN)6}]·3H2O obtained from [Mn(CN)6](3-) and D/L-aminoalanine, in contrast to one MGS for [{Mn(II)(L-NH2ala)}3{Cr(III)(CN)6}]·3H2O. They consist of three Mn(NH2ala) helical chains bridged by M(III)(CN)6 to give the framework with disordered water molecules in channels and between the M(III)(CN)6. Both MGS are characterized by a negative Weiss constant, bifurcation in ZFC-FC magnetizations, blocking of the moments, both components of the ac susceptibilities, and hysteresis. They differ in the critical temperatures, absolute magnetization for 5 Oe FC (lack of spontaneous magnetization for the SG), and the shapes of the hysteresis and coercive fields. While isotropic pressure increases both T(crit) and the magnetizations linearly and reversibly in each case, dehydration progressively transforms the FI into the SG as followed by concerted in situ magnetic measurements and single-crystal diffraction. The relative strengths of the two moderate Mn(III)-CN-Mn(II) antiferromagnetic (J1 and J2), the weak Mn(II)-OCO-Mn(II) (J3), and Dzyaloshinkii-Moriya antisymmetric (DM) interactions generate the two sets of characters. Examination of the bond lengths and angles for several crystals and their corresponding magnetic properties reveals a correlation between the distortion of Mn(III)(CN)6 and the MGS. SG is favored by higher magnetic anisotropy by less distorted Mn(III)(CN)6 in good accordance with the Mn-Cr system. This conclusion is also born out of the magnetization measurements on orientated single crystals with fields parallel and perpendicular to the unique c axis of the hexagonal space group.

Extended chronologies of aqueous alteration in the CM2 carbonaceous chondrites: Evidence from carbonates in Queen Alexandra Range 93005

The Antarctic CM2 carbonaceous chondrite QUE 93005 contains four compositionally distinct carbonates, namely breunnerite, calcite, dolomite and a Ca-poor dolomite. These carbonates can form monomineralic grains, or may be intergrown as bimineralic grains consisting of dolomite plus breunnerite and dolomite plus calcite, or polymineralic grains containing an intergrowth of breunnerite, Ca-poor dolomite and calcite. Carbonates in all grain types have inclusions of Fe–Ni sulphides and/or Mg–Fe phyllosilicates. In the bimineralic grains, dolomite crystallised first to be overgrown by breunnerite or partially replaced by calcite. Polymineralic grains are concentrically layered, with breunnerite crystallising first on pore margins to be later etched, then overgrown and partially replaced by Ca-poor dolomite that was itself partly dissolved prior to being overgrown by calcite. Calcite and dolomite have also cemented fractures that cross-cut the fine-grained rims to aqueously altered chondrules and were formed by expansion of the chondrules during their hydration. Overall, the sequence of mineralisation in QUE 93005 was: (1) dolomite, (2) breunnerite, (3) Ca-poor dolomite then (4) calcite. This secular change in carbonate composition and mineralogy reflects changing solution composition and probably also provenance. Mg–Fe phyllosilicates replaced dolomite, breunnerite and Ca-poor dolomite prior to calcite crystallisation, and most or all of the sulphides formed after both the phyllosilicates and calcite. Following sulphide crystallisation, the edges of carbonate grains were abraded, either by impact ‘gardening’ or as a consequence of fluidisation of the matrix during rapid loss of gas or vapour. Determination of the crystallisation age of dolomite via the Mn–Cr system indicates that aqueous alteration of QUE 93005 began on or before 3.93±0.23Ma after the formation of the oldest solar system solids. Overall, the water/rock ratio and fO2 during alteration of QUE 93005 was similar to that of the CM1s and CR1s, but the lower degree of alteration of QUE 93005 overall suggests that alteration timescales were shorter, possibly due to loss of intergranular liquid water during fluidisation.

High-precision 27Al/24Mg ratio determination using a modified isotope-dilution approach

The precision of the 26Al–26Mg system—one of the most widely used chronometers for constraining the relative timing of events in the early solar system—is presently limited by methods for the determination of 27Al/24Mg ratios, which have seen little improvement in the last decade. We present a novel method for the measurement of 27Al/24Mg ratios in unpurified sample solutions by multiple-collector inductively coupled plasma mass spectrometry. Because Al is monoisotopic we use a modified isotope dilution approach that employs a mixed spike containing isotopically enriched 25Mg and natural 27Al in an accurately known ratio. In order to determine the spike to sample ratio for Al, measurements of spiked aliquots are bracketed by unspiked aliquots, which negates the impact of elemental bias. Unlike conventional isotope dilution, samples do not require chromatographic separation prior to analysis, which both saves time and minimises the risk of contamination of other samples with spike (which is added immediately prior to analysis). Repeat measurements of the BHVO-2, BCR-2, and BIR-1 international rock standards, as well as a gravimetrically prepared Al–Mg reference solution, indicate that our method is both accurate and reproducible to 0.2%. This 4- to 10-fold improvement over previous methods translates directly to an equal gain in the resolution of the 26Al–26Mg chronometer. The approach presented here could, in principle, be applied to other monoisotopic elements such as the Mn–Cr system. Based on multiple measurements of a ∼2.7 gram piece of the Ivuna CI chondrite, we present a new estimate for the 27Al/24Mg ratio of this meteorite of 0.09781 ± 0.00029.

Active cooling of a metal hydride system for hydrogen storage

Reversible high-pressure metal hydrides offer excellent cold start capability and potentially increased hydrogen storage capacity. However, efficient thermal management is a critical issue in this kind of systems. In the present work, hydriding and dehydriding tests have been conducted with 100 g of Ti 1.1MnCr metal hydride at pressures up to 330 bar. Thermal characteristics of the Ti 1.1MnCr system have been quantified from the experimental data and simulated using a basic numerical model. By varying the coolant flow rates, a hydrogen filling time of 12 min has been achieved.

Fayalite in the Vigarano CV3 carbonaceous chondrite: Occurrences, formation age and conditions

We have performed petrographic characterization, 53Mn– 53Cr age determination and thermodynamic stability evaluations of fayalite in Vigarano meteorite that belongs to the reduced subgroup of CV3 chondrites. Vigarano is a breccia consisting of clasts which are separate chondrules surrounded by olivine-rich fine-grained materials. Four out of twenty three explored clasts contain fayalites that represent materials of the Bali-like oxidized subgroup of CV3 chondrites. The fayalites (Fa > 80 ) with grain sizes typically < 20 µm occurs in veins that extend from chondrules into the fine-grained materials. The fayalite commonly coexists with troilite and/or magnetite. The fayalite-bearing veins terminate at the boundaries of clasts. No evidence of strong impact enough to make melt veins is found in materials adjacent to the veins. These observations suggest that the fayalite-bearing veins in the Bali-like clasts formed through aqueous alteration in an asteroid prior to fragmentation and re-accretion to the Vigarano parent body. In saponite-rich fine-grained materials, we also found troilite–magnetite veins, which are similar to the fayalite-bearing veins in morphology. Morphological evidences and thermochemical equilibrium calculations suggest that fayalite replaced magnetite, and that replacement occurred at temperatures < 200 °C and low water/rock mass ratios from 0.07 to 0.18, which represent aqueous to metamorphic transition. Fayalite grains typically show iron-magnesium zoning (fayalite content decreases towards the grain edges). Based on equilibrium models, this zoning may have occurred at increasing temperature. The observed initial ratio of ( 53Mn/ 55Mn) 0 = (2.3 ± 0.5) × 10 − 6 suggests that fayalite formed ~ 5 Ma before the timing when the Mn–Cr system was closed in angrite NWA 4801 and has an absolute age of ~ 4563 ± 1 Ma. The age of fayalite is identical within errors to that in Mokoia and Kaba CV3 chondrites, which belong to the Bali-like oxidized subgroup. The identical age implies that aqueous alteration occurred at the same time in parent asteroids of Bali-like subgroup materials. These fayalite-bearing materials may have been derived from a single CV3 asteroid or from separate CV3 asteroids where aqueous alteration simultaneously occurred.

Cr diffusion in orthopyroxene: Experimental determination, 53Mn– 53Cr thermochronology, and planetary applications

We have determined Cr diffusion coefficients ( D) in orthopyroxene parallel to the a-, b-, and c-axial directions as a function temperature at f(O 2) corresponding to those of the wüstite–iron (WI) buffer. Diffusion is found to be significantly anisotropic with D(// c) > D(// b) > D(// a), conforming to an earlier theoretical prediction. Increase of f(O 2) from WI buffer conditions to 4.5 log unit above the buffer at 950 and 1050 °C leads to decrease of D(Cr) by a factor of two to three, possibly suggesting significant contribution from an interstitial diffusion mechanism. We have used the diffusion data to calculate the closure temperatures ( T c) of the Mn–Cr decay system in orthopyroxene as a function of initial temperature ( T 0), grain size ( a) and cooling rate for spherical and plane sheet geometries. We also present graphical relations that permit retrieval of cooling rates from knowledge of the resetting of Mn–Cr ages in orthopyroxene during cooling, T 0 and a. Application of these relations to the Mn–Cr age data of the cumulate eucrite Serra de Magé yields a T c of 830–980 °C, and cooling rates of 2–27 °C/Myr at T c and ∼1–13 °C/Myr at 500 °C. It is shown that the cooling of Serra de Magé to the closure temperature of the Mn–Cr system took place at its original site in the parent body, and thus implies a thickness for the eucrite crust in the commonly accepted HED parent body, Vesta, of greater than 30 km. This thickness of the eucrite crust is compatible only with a model of relatively olivine-poor bulk mineralogy in which olivine constitutes 19.7% of the total asteroidal mass.

Aluminum‐26 in H4 chondrites: Implications for its production and its usefulness as a fine‐scale chronometer for early solar system events

Abstract— In order to investigate whether or not 26Al can be used as a fine‐scale chronometer for early solar system events we measured, with an ion microprobe, Mg isotopes and Al/Mg ratios in separated plagioclase, olivine, and pyroxene crystals from the H4 chondrites Ste Marguerite (SM), Forest Vale (FV), Beaver Creek and Quenggouk and compared the results with the canonical 26Al/27Al ratio for calcium‐aluminum‐rich inclusions (CAIs). For SM and FV, Pb/Pb and Mn‐Cr ages have previously been determined (Göpel et al., 1994; Polnau et al., 2000; Polnau and Lugmair, 2001). Plagioclase grains from these two meteorites show clear excesses of 26Mg. The 26Al/27Al ratios inferred from these excesses and from isotopically normal Mg in pyroxene and olivine are (2.87 ± 0.64) × 10−7 for SM and (1.52 ± 0.52) × 10−7 for FV. The differences between these ratios and the ratio of 5 times 10−5 in CAIs indicate time differences of 5.4 ± 0.1 Ma and 6.1 ± 0.2 Ma for SM and FV, respectively. These differences are in agreement with the absolute Pb/Pb ages for CAIs and SM and FV phosphates but there are large discrepancies between the U‐Pb and Mn‐Cr system for the relative ages for CAIs, SM and FV. For example, Mn‐Cr ages of carbonates from Kaidun are older than the Pb/Pb age of CAIs. However, even if we require that CAIs are older than these carbonates, the time difference between this “adjusted” CAI age and the Mn‐Cr ages of SM and FV require that 26 Al was widely distributed in the early solar system at the time of CAI formation and was not mostly present in CAIs, a feature of the X‐wind model proposed by Shu and collaborators (Gounelle et al., 2001; Shu et al., 2001). From this we conclude that there was enough 26Al to melt small planetary bodies as long as they formed within 2 Ma of CAIs, and that 26Al can serve as a fine‐scale chronometer for early solar system events.

Magnetic structure of manganese overlayers on semi-infinite chromium substrate

We report a study of the magnetic behavior of ultrathin Mn films deposited on a Cr substrate using a real space tight binding approach. The magnetism is described in the Hartree–Fock approximation of the Hubbard Hamiltonian. The density of states is calculated within the recursion technique. The magnetic moments of Mn–Cr system up to three Mn overlayers for different crystallographic orientations {(001), (011), (111)} are calculated. The onset of magnetism depends on the faces considered. A sizable induced moment appears in the Cr interface layer. The calculations show ferromagnetic sheets of both metals for the planes {(001) and (111)} and magnetic c(2×2) configuration for the (011) plane. This behavior is consistent with the antiferromagnetic ground states of the constituents.

Liquid–solid equilibria in the Al-rich corner of the Al–Mn–Cr system

The aspect of the Al–Mn–Cr phase diagram related to liquid–solid equilibria in the subsection Al 4Cr–Al 4Mn–Al was investigated. It is shown that ternary Al 4Mn x Cr 1− x compounds (0≤ x≤1) whose structure correspond to that of the hexagonal μAl 4Mn phase, previously identified as a periodic approximant of Al–Mn and Al–Cr quasicrystalline phases, are in equilibrium with a liquidus phase field extending between both binary Al–Mn and Al–Cr limits. A new ternary Al–Mn–Cr phase, called Ψ, is also found and characterised. Its structure is monoclinic with cell parameters a Ψ=17.48 Å, b Ψ=30.31 Å, c Ψ=24.695 Å, β=135° and a space group of either C 2/ c or Cc symmetry . But as peculiar structural faults are observed in this monoclinic Ψ-phase, its formation is assumed to be the result of an allotropic transformation of an orthorhombic structure which would first solidify. Besides, from structural relationships observed between the μ and Ψ structures, it is suggested that the atomic structure of Ψ could also be typical of an arrangement of icosahedral clusters as, for instance, those defined in both the μAl 4Mn and λAl 4.5Mn structures.

Photoinduced magnetic pole inversion in a ferro–ferrimagnet: (Fe0.40IIMn0.60II)1.5CrIII(CN)6

We tried to design the magnet exhibiting magnetic pole (N and S) inversion by photostimuli. The magnetization of Fe1.5IICrIII(CN)6⋅7.5H2O was changed in a photon mode by visible light. A ferro-ferrimagnet (Fe0.40IIMn0.60II)1.5CrIII(CN)6⋅7.5H2O mixed by ferromagnetic (Fe–Cr system showing the change of magnetization by optical stimuli) site and ferrimagnetic (Mn–Cr system showing no optical response) site showed negative magnetization at the temperature lower than compensation temperature (Tcomp=19 K). In this mixed metal cyanide magnet we have succeeded in demonstrating a novel magnetic behavior “photoinduced magnetic pole inversion.” Moreover, the magnetic pole inversion can be induced repeatedly by alternate optical and thermal stimulations.

Vertical section of Fe–C–2Si–2Mn–1 Cr system for carbon contents up to 0·8 wt-% and associated phase compositions

Phase coexistence in the Fe–C–Si–Mn–Cr system, as the base system of a large number of low alloy steels, has been studied experimentally and theoretically. The vertical section of the phase diagram of the Fe–C–2Si–2Mn–1 Cr system near the eutectoid point (700–900°C; 0·14–0·80 wt-%C) and the chemical composition of the phases present were determined by means of scanning electron microscopy and energy dispersive X-ray analysis. Thermodynamic calculations of the Fe–C–Si–Mn–Cr system equilibria, based on the Hillert–Staffansson model, for low contents of silicon, manganese, and chromium were performed. These calculations gave results very close to both the experimentally determined phase boundaries and the composition of phases. A wide eutectoid zone (about 50 K) was found to exist in the system, for all carbon contents studied.MST/1940

Vertical section of Fe–C–2Si–2Mn–1 Cr system for carbon contents up to 0·8 wt-% and associated phase compositions

Abstract Phase coexistence in the Fe–C–Si–Mn–Cr system, as the base system of a large number of low alloy steels, has been studied experimentally and theoretically. The vertical section of the phase diagram of the Fe–C–2Si–2Mn–1 Cr system near the eutectoid point (700–900°C; 0·14–0·80 wt-%C) and the chemical composition of the phases present were determined by means of scanning electron microscopy and energy dispersive X-ray analysis. Thermodynamic calculations of the Fe–C–Si–Mn–Cr system equilibria, based on the Hillert–Staffansson model, for low contents of silicon, manganese, and chromium were performed. These calculations gave results very close to both the experimentally determined phase boundaries and the composition of phases. A wide eutectoid zone (about 50 K) was found to exist in the system, for all carbon contents studied.MST/1940

Developments in austenitic steels containing manganese

AbstractTwo broad categories of austenitic steels are considered in this review: (a) alloys based on the Fe–Mn–C system, typified by austenitic wear resistant (Hadfield) steels and (b) alloys based on the Fe–Mn–Cr system, typified by austenitic corrosion resistant steels. Advances made in recent years in understanding and improving the relevant properties and manufacturing methods of these steels are critically appraised. The development of austenitic manganese bearing high technology steels for fusion reactor and other non-magnetic applications, as well as those that can be used in cryogenic structures, is also considered.

Preparation chemistry and phase transitions in the ZnMnCr system

Preparation chemistry and phase transitions in the ZnMnCr system